STRUKTUR MIKROSKOPIK DAN MINERALOGI GALZUR KERAMIK HASIL PERCOBAAN DENGAN FORMULA GA DAN GZ

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

STRUKTUR MIKROSKOPIK DAN
MINERALOGI GALZUR KERAMIK HASIL
PERCOBAAN DENGAN FORMULA GA
DAN GZ

Sudarsono dan Eko Tri Sumarnadi

Pusat Penelitian Geoteknologi – LIPI

Abstrak

Percobaan pembuatan glazur keramik berbahan baku limbah pemotongan batu
templek telah dilakukan dan menghasilkan prototipe jenis transparant, semi
mat dan mat. Limbah pemotongan batu yang digunakan berasal dari Palimanan
Cirebon dan berkomposisi tuf andesitan. Formula pembuatan glazur dari bahan
limbah asli ditandai dengan formula GA, dan yang diberi bahan tambahan
ditandai dengan formula GZ.

Hasil percobaan dibuat sayatan tipis sejajar permukaan dan tegak lurus
permukaan untuk diamati dibawah mikroskop. Struktur mikroskopis yang dapat
diamati adalah restit penggelasan, infiltrasi ke dalam badan keramik,
gelembung udara dan retakan. Dan mineralogi yang terlihat adalah tingkat
pelelehan dan proporsi mineral tertentu. Baik Formula GA maupun GZ samasama
menunjukkan kecenderungan semakin tinggi proporsi relatif SiO2
terhadap Al2O3 semakin kurang menggelas atau mat, semakin banyak
gelembung dan retakan. Sebaliknya semakin kecil baik proporsi relatif SiO2
maupun Al2O3 semakin banyak yang menggelas, semakin sedikit restit mineral
dan retakannya.

Glazur yang bersifat transparant dan licin dihasilkan oleh formula GA dan GZ
yang mempunyai proporsi relatif SiO2 dan Al2O3 rendah, sedangkan glazur yang
bersifat dof, kurang licin atau mat dihasilkan oleh formula baik GA maupun GZ
yang mempunyai proporsi relatif SiO2 dan Al2O3 tinggi. Penambahan bahan
tambahan pada formula GZ berpengaruh terhadap tingkat kekusaman atau
keburaman glazur dan sedikit berpengaruh terhadap penggelembungan dan
peretakan. Penggelembungan dan peretakan mikro kemungkinan ditimbulkan
oleh keluarnya hidroksil dari mineral-mineral hydrous pada saat pembakaran
setelah unsur silika sudah mulai menggelas.

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HYDRAULIC CONDUCTIVITY BEHAVIORAL DEVELOPMENT ON ARTIFICIAL VEGETATION SUBSTRATES (MADE BY COAL FLY ASH, GRAVEL G5 AND CLAY) FOR THE COAL MINING RECLAMATION PROJECT ”OBERDORF“ GKB-BERGBAU GMBH KÖFLACH AUSTRIA

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

HYDRAULIC CONDUCTIVITY
BEHAVIORAL DEVELOPMENT ON
ARTIFICIAL VEGETATION SUBSTRATES

(MADE BY COAL FLY ASH, GRAVEL G5 AND CLAY)

FOR THE COAL MINING RECLAMATION
PROJECT ”OBERDORF“ GKB-BERGBAU
GMBH KÖFLACH AUSTRIA

Anggoro Tri Mursito

Research Centre for Geotechnology, Indonesian Institute of Sciences (LIPI)

Abstract

The open pit coal mine “Oberdorf” located about 30 km north of Graz is the
biggest one in Austria. Coal production will cease in 2004 leaving an area of
350 hectares of which about 80% have to be recultivated and/or reclaimated.
The key issue of this research is to develop an optimized substitute for the
missing biologically active topsoil, which was dumped during mining activity, as
well as to figure out adjusted vegetation in dependence from the composition of
the “artificial” soil.

An artificial soil mixed made out of electrical-coal power plant wastes (fly ash)
and material from the mine (clay and gravel G5) has been created for the
reclamation of open pit mine site. Physico-chemical properties were measured
over time to examine them in a chronosequence of 22 plots (each 400m2) with
systematically changing mixtures (1,2 and 3 components of varying proportions
were established and planted. In the field plots, available nutrient content was
initially high but established only for some of plots. Due to ecological function
measurement, physical parameter, which is hydraulic conductivity, is one of
several physic properties will have to be monitored and analysed.

According to the development value of the year of 2003 (spring) shows that
increasing of water permeability classes (class 6) is leaning to the direction of
fly ash and tegel composition. Class 5 are only in the trial plot number 5 and 9.
Only in one trial plot which is drop in class 4 (trial plot 16), but it is still classified
into “good” class (according to “Arbeitskreis Standortskartierung, 1996”). The
trial plot number 1 has also classified into class 6, because the substrate
composition in this trial is only 100% of gravel. It has to be the highest class, but
it is not always the highest value of water permeability. All the trial plots are
classified into high to very-very high. Compared results between initial (spring, 2000) and recent measurement (spring, 2003) is shown that extremely
increased in the trial plot 3 and 13. In the year of 2003, in trial plot number 3
and 13 are suddently flare up to 4 classes (from class 2 to 6). As we can see in
the CT images of one component substrate (100 % of tegel) shows that cracked
structures clearly appear as a results of decreasing precipitation in the last
winter and also highly increasing of temperature as well. High percentage of
cracked means that water can easily flows. Most of the trial plots are increasing
of classes due to the season differences. The others (trial plot number 1, 5, 6
and 9) remain in the same class. Same grade doesn’t means that same value of
water permeabilty as well, but e.g. trial plot 1 has same class compared to the
result in 2000 and that means very very high.

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SALT INTRUSION MODEL AND SYSTEM IMAGING BY USING 3-D GEOPHYSICAL INVERSION TECHNOLOGY: CASE STUDY OF TANGGERANG AREA

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

SALT INTRUSION MODEL AND SYSTEM

IMAGING BY USING 3-D GEOPHYSICAL

INVERSION TECHNOLOGY: CASE STUDY OF

TANGGERANG AREA

T.A.Sanny* and Denny Juanda P**

*Departemen Teknik Geofisika ITB, **Departemen Fisika ITB

Abstract

The paper describes the application of the relatively new technology in the
world level, and the research on this is probably the first in Indonesia. From this
research works, the aquifer can be imaging by using inverse resisitivity and
GPR technology in 3-D to know salt intrusion model and system in Tangerang
Area, Banten Province. By using this technology we know a lot of subsurface
condition visually such as stratigraphy, seepage, aquifer, aquitar and etc. By
the paper, we want to show that the result of the inversion imaging of
geophysical technology is very powerfull to make the new scanning capability
in any application. As a case study experiment is Tangerang area, which is a lot
of population and industrial activities.

An interesting resistivity image of the aquifer, which shows is various of
resistivity values. High resistivity zone interpreted as aquitar and Low resisivity
zone interpreted as aquifer. Some area having very low resisitivity which
interpretated as salt water. We discuss the image reconstruction result of
auifer model and system and how to differ between salt water formation and salt
water intrusion in accuratelly.

Abstrak

Makalah mengungkapkan penerapan teknologi yang relative baru dalam tingkat
dunia, akan tetapi kemungkinan baru pertamakali diterapkan di Indonesia.
Penelitian ini mengungkapkan pencitraan akifer dengan teknologi inversi
resisitivitas dan GPR dalam 2-D dan 3-D diterapkan untuk mengetahui model
dan sistem akifer daerah Tangerang, Provinsi banten. Dengan menggunakan
teknologi ini kita dapat mengetahui banyak hal kondisi bawah permukaan
seperti struktur geologi, stratigrafi, rembasan, zona lapuk, akifer, akitar, dan
sebagainya secara visual. Dalam makalah ini kami ingin memperlihatkan
kemampuan teknologi pencitraan akifer dengan berbagai kepentingan. Sebagai
contoh kasus adalah Daerah Tangerang yang padat dengan penduduk dan
aktivitas industri.

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GROUNDWATER POTENCY IN INDONESIA

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

GROUNDWATER POTENCY IN
INDONESIA

Haryadi Tirtomihardjo

Abstract

In Indonesia, groundwater has a significant role in providing water for various
purposes, that is, drinking water in rural areas, drinking water and industry in
urban areas, and for irrigation supplement. A sustainable groundwater
utilization, hence, needs groundwater management with a proper manner. As
stipulated on paragraph 12 article (2) of Law No. 7 of 2004 on Water
Resources, “groundwater management is based upon the groundwater
basin”; that is, management should cover an area which is limited by
hydrogeologic boundaries, where the hydrogeologic events such as recharging,
flowing, and discharging of groundwater occur. It shows legally clarification on
shifting from management of wells (well management) to the management of
groundwater basins (groundwater basin management) which is aiming at the
conservation of groundwater.

In Indonesia has been identified 396 groundwater basins, mainly distributed in
the larger islands which have total groundwater potency about 638 milyard
m3/year. In Java and Madura islands, 80 groundwater basins were identified
which have total groundwater potency about 54 milyard m3/year. Various
extends of groundwater basin depending on the hydrogeologic conditions of the
area. Generally, at the larger islands such as Papua, Kalimantan, Sumatera,
and Java the groundwater basins are widely extended, while at the smaller
islands such as Nusa Tenggara and Maluku are relatively small extended.
Overlaying the groundwater basin and administrative boundaries of
kabupaten/kota shows four type of groundwater basins, i.e. groundwater basin
which are crossing province, kabupaten/kota, and state boundaries, as well as
groundwater basin which is fully in the kabupaten/kota boundaries.

Detail information on groundwater potency of each groundwater basin is
absolutely needed in order to establish the groundwater utilization plan. Such
information can be obtained by investigation which comprises study and
assessment on lateral and vertical boundaries of the groundwater basin,
configuration and parameter of aquifer systems, quantity and quality of
groundwater, recharge and discharge areas, and its degree of the groundwater
potency.

 

Abstrak

Di Indonesia, air tanah memegang peran penting sebagai air baku untuk
penyediaan air minum di daerah pedesaan, air minum dan industri di daerah
perkotaan, suplesi irigasi, dan sebagainya. Agar pemanfaatan air tanah untuk
berbagai keperluan itu dapat dijamin secara berkelanjutan diperlukan
pengelolaan air tanah secara benar. Pasal 12 ayat (2) Undang-Undang Nomor
7 Tahun 2004 tentang Sumber Daya Air menetapkan bahwa pengelolaan air
tanah didasarkan pada cekungan air tanah, yakni suatu wilayah yang dibatasi
oleh batas hidrogeologis, tempat semua kejadian hidrogeologis seperti proses
pengimbuhan, pengaliran, dan pelepasan air tanah berlangsung. Itu berarti
penegasan secara legal adanya perubahan paradigma dalam pengelolaan air
tanah, yang semula berdasarkan pengelolaan sumur (well management)
menjadi pengelolaan cekungan air tanah (groundwater basin management)
dengan tujuan konservasi air tanah.

Jumlah cekungan air tanah di Indonesia telah diidentifikasi sebanyak 396
cekungan air tanah, terutama tersebar di pulau-pulau besar dengan total
potensi mencapai sekitar 638 milyar m3/tahun. Sebanyak 80 cekungan air tanah
di antaranya terdapat di P. Jawa dan P. Madura dengan potensi air tanah
sekitar 54 milyar m3/tahun. Luas cekungan air tanah beragam tergantung
kepada kondisi hidrogeologis setempat. Umumnya di pulau-pulau besar seperti

P. Papua, P. Kalimantan, P. Sumatera, dan P. Jawa cukup luas, sedangkan di
pulau-pulau kecil seperti di Nusa Tenggara dan Maluku dijumpai cukup sempit.
Dikaitkan dengan batas wilayah kepamongprajaan, lamparan cekungan air
tanah sebagian bersifat lintas provinsi, lintas kabupaten/kota, lintas negara, dan
utuh berada dalam wilayah kabupaten/kota.
Sebagai dasar dan acuan dalam perencanaan pendayagunaan air tanah,
diperlukan informasi potensi setiap cekungan air tanah tersebut melalui
pengkajian secara rinci dan komprehensif yang mencakup penentuan sebaran
cekungan air tanah secara lateral dan vertikal, konfigurasi dan parameter
sistem akuifer, kuantitas dan kualitas air tanah, daerah imbuhan dan daerah
lepasan air tanah, serta tingkat potensi air tanah

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THE EVOLUTION OF SATONDA VOLCANO ISLAND, WEST NUSA TENGGARA PROVINCE

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

THE EVOLUTION OF SATONDA
VOLCANO ISLAND, WEST NUSA
TENGGARA PROVINCE

Heryadi Rachmat & Mujitahid Iqbal

IAGI – Pengda Nusra

Abstract

Satonda is a volcano island (±285 m) which raised from about 1000 meter water
depth, its geographical coordinates are 8°7’ South latitude and 117° 45’ East
longitude, 28 kilometres northwest Tambora volcano. It’s widely 4.8 km square
with two calderas forming 8 number-shape lake 0.8 km square in wide and 0.03
km qubic in volume, shield volcano made up of pyroclastics and basaltic lava.
The first careter 400 meter in diameter and 39 m in depth, and the second
crater is 950 m in diameter with 69 m in depth. Based on the similarity to
Tambora volcano, 100 – 200 thousand years old in age (Takira Akada, 2002).
After forming both of the craters, more than 4000 yaers ago (Kempe Stephan,
1995) the craters has collapsed so the island submerged by seawater and
widely growth by a coral reefs platform (Cyanobacteria dan Red algal
calcareous), and then uplifted occur so the coral reef died.

Originally, the lake water was fresh water, but due to tsunami as a result of Mt.
Tambora explosion on 15 April 1815, the water of Satonda lake has turned
salty, so it is not due to the tunnel below the lake surface which has been
thought of by many people. The influence of 1815 eruption on the lake
chemistry and resulting lithological and biotic changes.

Abstrak

Satonda merupakan pulau gunung api (±285 m) yang muncul dari kedalaman
1000 m, terletak pada koordinat 8º7’ Lintang Selatan dan 117°45’ Bujur Timur,
28 km sebelah barat laut Gunung api Tambora. Luasnya ±4,8 km2, memiliki
dua buah kawah menyerupai angka delapan membentuk danau seluas 0,8 km2
dengan volume sekitar 0,03 km3, dinding kawahnya terdiri dari perlapisan
piroklastika serta lava. Kawah pertama berdiameter 400 m kedalaman 39 m,
kawah kedua berdiameter 950 m kedalaman 69 m. Berdasarkan
kesebandingan dengan Gunung api Tambora Tua, umurnya antara 100 - 200
ribu tahun (Takada Akira, 2002). Setelah pembentukan kedua kawah di atas,
lebih dari 4000 tahun lalu (Kempe Stephan, 1995) telah terjadi penurunan
sehingga kedua kawah terendam laut dan tumbuh terumbu karang
(Cyanobacteria dan Red algal calcareous) yang cukup luas, kemudian terjadi
pengangkatan sehingga semua karang mati. Letusan dahsyat Gunung api Tambora 15 April 1815 menimbulkan tsunami
yang menyebabkan sebagian air laut dan ikan terbawa masuk ke dalam danau
Satonda. Akibat perubahan lingkungan tersebut telah menyebabkan
berubahnya sifat fisik ikan. Saat ini Pulau Satonda merupakan salah satu
prioritas daerah tujuan wisata geologi (Geowisata) yang cukup diandalkan.

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THE ROLE OF ENVIRONMENTAL GEOLOGY IN KARST REGION MANAGEMENT

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

THE ROLE OF ENVIRONMENTAL
GEOLOGY IN KARST REGION
MANAGEMENT

Rudy Suhendar, Ruswanto, Guntarto

Directorate of Environmental Geology and Mines Area

Abstract

Nowadays, many people and institutions have interest on karst region, in the
karst region have many variety of geological (geodiversity), and biological
(biodiversity), and economic potential for current time and in the future.
However, the karst region are well known vulnerable to environmental damage,
So that, karst region are needed a right multi sectors management, which are,
bring a guarantee of increasing communities prosperity and suistainable
development, without ignoring karst conservation.

The role of environemtal geology for karst regions management is preparing
data of environmental geological setting, such as geology, geomorphologic
feature, hydrogeology and geological hazard. These data are ones basic data
for land use and spatial planning or karst region, beside for determining karst
regions boundaries and karsts classifiaction.

Classification and land use determination are a buffering system for karst region
conservation with keeps of allowed land use. In the reommended land use, for
each class region of karsts shoild be consider geological factors that have a role
as supporting and contrains for development. A supporting aspects are using
such as morphology, water resources, soil thickness and fertility, and foundation
bearing capacity. Constrains aspect are suspectibility to landslide and soil
erosion.

Determination of karst region begins with separating limestone area (and
dolomite) with non-limestone rock. Furthermore to separate of limestone which
has karstification with limestone do not have karstification. Karst classification
only did on the karst limestone.

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BENCANA ALAM GERAKAN TANAH DI DAERAH CILILIN, KABUPATEN BANDUNG DAN RENCANA RELOKASINYA

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

BENCANA ALAM GERAKAN TANAH DI
DAERAH CILILIN, KABUPATEN
BANDUNG DAN RENCANA
RELOKASINYA

Herry Purnomo

Direktorat Vulkanologi dan Mitigasi Bencana Geologi

Abstract

Landslide occured in Walahir, Kidang Pananjung village, Cililin sub district,
Bandung district, West Java province on April 21, 2004 at 21.00 pm. The
disaster caused : 12 people died, 3 lost, 6 heavy wounded, 9 wounded, 21
houses burried, 22 houses distroyed and 60 Ha of rice field and 85 Ha
plantation burried by debris. The site as hilly area with slope of 15 - 450,
elevation 1.000 - 1.100 meter from sea level. The slide derived from the upper
part which has slope angle of 350 when the housing area lied beneath the
slope and channel of valley. Rock composed of weathered andesitic breccia,
the thicness of soil 1 - 2,5 meter. Landuse consist of mixed platation and field
on upper slope and rice field and settlement beneath the slope. In the middle
slope found spring.

The landslide as debris slide with 35 meter length, 10 - 40 meter width, heiju of
scarp 1 - 3 meter to last ward. The cause of landslide were heavy rain, the
thickness of weathered for steep slope, bed rock upper….., none of plantation
which has strong the roof. The area recommended as alert area and forbidden
for settlement to relocation would be conducted, followed with reboisation.
The relocation area was in Cikopeng village Cililin subdistrict, Bandung district
which covers 2,8 Ha. Morphology as hilly prolayed soft undulating, slope 0 - 60,
elevation 1.108 - 1.114 meter from the sea level. Bed rock the area is
compacted breccia with thin soil 0,25 - 1,0 meter. Land use as bushy any field
near the road between Kidang Pananjung - Cililin. Water can be used from
spring ( 5 lt / sec. ) from Gedugan hill which 2 km from west part by using pipe.

Abstrak

Bencana alam gerakan tanah terjadi di Kp. Walahar, Ds. Kidang Pananjung,
Kec. Cililin, Kab. Bandung, Jawa Barat, pada tanggal 21 April 2004 sekitar jam

21.00 wib. Akibat bencana menyebankan 12 orang meninggal dunia, 3 hilang, 6
luka berat, 9 luka ringan, 21 rumah tertimbun, 22 rumah rusak berat, 60 Ha
sawah dan 85 Ha ladang tertimbun material longsoran. Kondisi daerah bencana
merupakan lereng perbukitan berkemiringan 15 -450 , ketinggian 1.000 - 1.100
m dpl. Longsoran terletak pada lereng atas berkemiringan 350, pemukiman
yang terlanda terletak pada bawah lereng dan alur lembah. Batuan penyusun
berupa breksi andesit yang lapuk di permukaan, tebal 1 - 2,5 meter. Tata lahan
berupa kebun campuran dan ladang di lereng atas serta sawah dan pemukiman
pada lereng bawah, sedang keairan terdapat mata air kecil pada lereng bagian
tengah.

Kondisi gerakan tanah berupa longsoran bahan rombakan, panjang 35 m, lebar
10 - 40 m, tinggi gawir 1 - 3 m arah ke timur, berkembang menjadi aliran bahan
rombakan yang mengalir sepanjang 270 meter dan melanda pemukiman.
Penyebab gerakan tanah adalah : hujan lebat yang lama sebelum kejadian,
tanah pelapukan yang tebal dan gembur, kemiringan lereng yang terjal, batuan
dasar yang kedap air, dan tidak ada tanaman keras berakar kuat dan dalam
pada lereng. Rekomendasi penanggulangan : daerah tersebut sudah tidak
layak huni, pemukiman pada lereng dan alur lembah perlu direlokasi ke tempat
aman, tidak membangun di daerah berlereng terjal dan lembah sungai,
menghijaukan kembali perbukitan dengan tanaman keras berakar kuat dan
dalam, pengolahan tanah perlu kewaspadaan tinggi.

Rencana relokasi pemukiman terletak di Kp. Cikopeng, Ds. Kidang Pananjung,
Kec. Cililin, Kab. Bandung, dengan luas 2,8 Ha. Morfologi berupa punggungan
perbukitan bmemanjang bergelombang lemah - sedang, kemiringan 0 - 60,
ketinggian 1.108 - 1.114 m dpl. Batuan dasar breksi kompak dengan pelapukan
tipis (0,25 - 1,0 m). Tata lahan berupa padang alang-alang dan tegalan dan
terletak ditepi jalan aspal antara Kidang Pananjung - Cililin. Keairan dapat
diambilkan dari mata air (debit 5 lt/dt) pada bukit Gedugan yang berjarak 2 km
sebelah barat lokasi ini dengan cara perpipaan.

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PROSES PENDANGKALAN SELAT MADURA, JAWA TIMUR

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

PROSES PENDANGKALAN SELAT
MADURA, JAWA TIMUR

Y. Darlan, Agus Setya Budhi dan Asep Faturachman
Pusat Penelitian dan Pengembangan Geologi Kelautan

Abstract

The coast of Madura Strait and adjacent areas belong to the environment
ecosystem of Bengawan Solo delta Complex. The coastal area has been known
as a marine shipping and has abundant marine biota resources. As the
increases in development of Surabaya City particularly at the north areas, such
as development of coastal areas for modern properties and industries, therefore
the have intensified the changes of coastal system of the area. Reclamation for
industries and living areas is a main priority in development programs for this
area. Reclamation of mangrove forest for industries and coastal fishery areas
affects to coastal erosion in the Madura Strait. Other effects are sedimentation
and deposition, which will no longer narrow the marine shipping of the Madura
Strait. Coastal waves generated by vessels and speedboats affect to coastal
erosion and water turbidity of the Madura Strait.

Abstrak

Kawasan pantai Selat Madura dan sekitarnya merupakan bagian dari ekosistem
lingkungan pantai delta Bengawan Solo. Kawasan pantai ini telah lama dikenal
sebagai alur pelayaran serta mempunyai sumberdaya pesisir dan laut yang
cukup banyak. Sejalan dengan pesatnya pengembangan kota Surabaya
khususnya di wilayah utara, seperti pengembangan kawasan pesisir untuk
daerah hunian modern (properti) dan industri, maka kondisi ini telah merubah
sistem pantai di kawasan tersebut. Lahan pantai untuk diurug (reklamasi)
sebagai daerah industri dan hunian merupakan prioritas dalm program
pengembangan daerah ini. Reklamasi hutan mangrove untuk dijadikan daerah
industri dan tambak menimbulkan dampak terjadinya erosi dataran pantai Selat
Madura. Dampak lainnya terjadi pendangkalan dan sedimentasi yang lambat
laun akan memepersempit daerah alur pelayaran Selat Madura. Gelombang
yang dibangkitkan oleh kapal-kapal yang berlaju cepat cukup memberikan
dampak terhadap erosi pantai dan keruhnya air di sekitar perairan Selat
Madura.

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THE CALDERA RINJANI OF LOMBOK, INDONESIA DURING THE LAST TEN THOUSAND YEARS

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

THE CALDERA RINJANI OF LOMBOK,
INDONESIA DURING THE LAST TEN
THOUSAND YEARS

Asnawir NASUTION*, AkiraTAKADA**, Ryuta FURUKAWA**
Rosgandika MULYANA* and Roni FATUROCHMAN*

Directorate of Volcanology and Geological Hazard Mitigation
Geological Survey of Japan, 1-1-1 Higashi, Tsukuba, 305-8567, Japan

Abstract

Remote sensing survey has been conducted in Rinjani complex of Lombok
Island. JERS-1 SAR has all weather observation capability and provide a
valuable image in the region. The interpreted geological information are shown
by drainage patterns, texture and lineaments. The volcanic rocks of West and
East Rinjani complexes are characterized by rough texture and high resistance.
The Central Rinjani complex is characterized by radial drainage patterns in low
density, smooth textures and low resistance. Lineament trends of N-S, NE-SW
and E-W are represented by old and young Rinjani complexes, probably
indicate an influence of subduction zone from the Indian – Australian plate to
the south. The eruptive histories and related to caldera formation during the last
10 ky are recognized by 14C dating. The eruption rate was kept constant (0.6
km3/ky) during a stratocone building stage between 12-6 ka. It decreases
becoming 0.15 km3/ky for the last period of 5.2 ky before the caldera forming
eruption (6-8 ka). During the low activity stage, three eruptions occurred;
Propok Pumice and Lembar Lava Flow (DRE: 0.1 km3 and 0.4 km3,
respectively), Rinjani Ash and Rinjani Pumice (DRE: 0.3 km3). The magma
path shifted 5 km toward the eastern flank to grow Rinjani volcano. The volcanic
activity migrated more 5 km eastward for low activity stage, erupting Propok
Pumice and Lembar Lava Flow. The activity migrated back to Rinjani summit
yielded ash and pumice. Syn-caldera stage started with plinian pumice (DRE: 3
km3) and a huge pyroclastic flow (DRE: >7 km3), and, finally, Segara anak
caldera of 6 km x7 km was formed at the centre of Central Lombok Volcanic
Complex. The climax of caldera forming eruption was the period of AD 12101300
years B.P. The collapse caldera remnants represent few alteration dykes
and fault structures with dipping 15 to 40o, on the north, south and east caldera
walls, probably indicating a flowing up magma through the old vents and weaker
structures before occurring the caldera formation.

Keywords: remote sensing, caldera, pyroclastic flow, Plinian eruption, eruption rate, Rinjani volcano,
Lombok island

»»  read more

EARTHQUAKE HAZARD AND RISK ZONATIONS OF THE SUMATERA ACTIVE FAULT (SEGMENT SIANOK), BUKITTINGGI AND SURROUNDING AREA

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

EARTHQUAKE HAZARD AND RISK
ZONATIONS OF THE SUMATERA ACTIVE
FAULT (SEGMENT SIANOK),
BUKITTINGGI AND SURROUNDING AREA

A. Soehaimi *, A. Djuhanda*, I.Effendi*,
I. Haryanto**, Ismawan**, Y. Fikri**
* Puslitbang Geologi Bandung, ** Jurusan Geologi Unpad
Abstract

The geology of Bukittinggi and surrounding area can be divided into 4 rock
groups: the Pra-Tertiary (metamorphic carboniferous sediment rock, ultra mafic
rock), The tertiary (granite intrusion), The Quartenary (volcanic rock), The
Holocene groups (alluvium and collovium deposits).

The structural geology (studied) in this region consist of 7 faults, there are: The
Sumatra Right Lateral Strike Slip Fault, The Padang Laweh Oblique Fault, The
Gaduik Right Lateral Strike Slip Fault, The Matur Thrust Fault, The Padang
Panjang Thrust Fault, The Simabur Normal Fault, The Tanjung Sawah Normal
Fault.

The displacement rate of river and layer of rocks along the Sumatera Fault
during ± 10.000 years (Marapi and Singgalang volcanic rocks age), The
Sumatera fault can be classified into the A Class active fault base on the
Matsuda's active faults criteria (1973). The maximum intensity base on
Watabe's method (1973) at Bukittinggi and Padang Panjang are VII-VIII MMI
(7.43-7.46 MMI).

The peak ground acceleration base on Murphy-O'Brien's and Kanai's method
using the 1926 Padang Panjang and 2004 Batipuh eatrhquake data showed the
Bukittinggi has peak ground acceleration 394.44 gal and 112.9 gal, while in
Padang Panjang has peak ground acceleration 486,3 gal and 177,87 gal.

Base on the geological condition, seismicity and infrastructure analysis, this
region can be divided into 6 earthquake hazard and risk zones, there are: The
High Hazard and Risk IA and IB Zones, The Intermediate Hazard and Risk IIA
and IIB Zones, The Low Hazard and Risk IIIA and IIIB Zones.

»»  read more

SO2 FLUX MEASUREMENT BY DOAS DOAS (DIFFERENTIAL OPTICAL ABSORPTION SPECTROSCOPY) AND ITS APPLICATION AT BROMO ERUPTION ON JUNE 2004

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

SO2 FLUX MEASUREMENT BY DOAS
DOAS (DIFFERENTIAL OPTICAL
ABSORPTION SPECTROSCOPY) AND ITS
APPLICATION AT BROMO ERUPTION ON
JUNE 2004

Hanik Humaida and Yustinus Sulistyo

BPPTK-Direktorat Volkanologi dan Mitigasi Bencana Geologi

Abstract

SO2 is one of the volcanic gases that can provide information about the state of
volcano activity, Commonly, SO2 flux is measured by COSPEC (Correlation
Spectroscopy). This equipment has several disadvantages; such as heavy, bog
size, expensive and stastic operation only. DOAS (Differential Optical
Absorption Spectroscopy) is anew method for SO2 gas flux monitoring that has
advantages compares to the COSPEC. Recently, this method has been
developed. This DOAS consist of 5 units; namely scan miler, condenser lens,
detector, power supply, and a laptop. Its total wieght is up to 11 kg. For
operation of DOAS using traverse method, it need lens unit, detector and
laptop. The weight is only 2 kg DOAS can be operated as static or traverse
method and can be mounted at anyplace.

Measurement of SO2 flux by DOAS has been done at G. Bromo on 12-15 June
2004, after the 8 June eruption. Location of neasurementis about 2 km from
eruption source using tripod. This angle of measurement ranges between 10o
and 12o width of scan is 45 o. Data was analysed by HINAGATA sofware. The
result showed that 30 minutes before the volcano produced ash, the flux of SO2
increased from normal condition until 135 ton/day.

Abstrak

Gas SO2 merupakan salah satu gas yang dapat memberikan informasi tentang
keadaan aktifitas suatu gunungapi. Pengukuran SO2 fluks biasanya dilakukan
dengan COSPEC (Correlation Spectroscopy). COSPEC mempunyai beberapa
kelemahan antara lain berat ukuran sangat besat, mahal, dan harus
dioperasikan secara statis. DOAS (Differential Optical Absorption
Spectroscopy) merupakan metoda baru yang digunakan untuk monitoring fluks
SO2 yang mempunyai beberapa kelebihan, yang sampai saat ini masih terus
dikembangkan. Alat ini terdiri dari 5 bagian yaitu : scan miler, condenser lens,
detector, power supalai dan note PC. Berat total alat ini sampai 11 kg. Untuk

Geo-Environment & Hazard

78

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

metoda lintasan yang diperlukan hanya condenser lens, detector dan note PC,
dengan berat hanya 2 kg. DOAS dapat dioperasikan secara statis maupun
gerak dan dapat ditempatkan dimana saja.

Telah dilakukan pengukuran fluks SO2 di G. Bromo pada tanggal 12-15 juni
2004 setelah erupsi 8 June denga DOAS. Lokasi pengukuran dilakukan pada
jarak 2 klm dari pusat letusan dengan metoda triport, kemiringan DOAS
terhadap Plume 10 o – 12o, lebar scan 45o. Data diolah dengan
sofwerHINAGATA. Hasil pengukuran menunjukkan bahwa kurang/lebih 30
menit sebeluim terjadi letusan abu ada peningkatan fluks gas dari kondisi
normal 20 ton/hari menjadi 135 ton/hari.

»»  read more

SEISMIC HAZARD ASSESSMENT: IN THE CASE STUDY OF MINESITE AREA-CENTRAL KALIMANTAN

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

SEISMIC HAZARD ASSESSMENT: IN THE
CASE STUDY OF MINESITE AREA-CENTRAL KALIMANTAN

Engkon K. Kertapati

Geological Research and Development Centre,

Abstract

The low-seismicity Central Kalimantan has never experienced any earthquake
damage. Thus, earthquake-resistant design has not been specifically required
in the building codes. However, it has been realized that urban and mine areas
located rather distantly from earthquake sources may also be affected by
tremors. The key is basically determined by how well seismic hazards derived
from seismic potency can be estimated. In this paper, the potential ground
motion in terms of the peak ground accelerations (PGAs) due to long – distance
East Kalimantan and West Sulawesi earthquakes (far field earthquake) is
investigate, following a probabilistic seismic hazard assessment approach.
Earthquakes that have occurred in radius of 500 km (far field) in the last 50 year
are used. Based on the PGAs of more than 50% East Kalimantan and West
Sulawesi earthquakes recorded in Central Kalimantan, the attenuation
relationship of Fukushima and Tanak (1992) is found to correlate well with the
high-rate attenuation characteristic of the region. The predicted design basis
PGA for Tailings Dam, i.e., PGA with 10% probability of being exceeded in a
20-year exposure time, on rock outcrops site is 0.041 g (g=gravity value), or

0.103 g on soft soil. And 0.105 g with 10% probability of being exceeded in a
1000 year exposure time on rock ou-crops or 0.261 g for soil. However, the
increasing number of felt tremors in recent yaers demonstrates suc as:
Muarateweh earthquake, which occurred on July 05, 1996, that although no
significant damage was report, the earthquake was strongly felt.
Keywords: ground acceleration, ground-motion, attenuation function, earthquake-resistant
design.

Abstrak

Kalimantan Tengah dengan tingkat kegempaan yang rendah, tidak pernah
mengalami gempabumi merusak. Oleh karena itu, rancangan bangunan tahan
gempa, secara khusus tidak diperlukan dalam kode bangunan. Walaupun
demikian, perkotaan dan daerah-daerah penambangan yang agak berjarak dari
sumber-sumber gempabumi dapat dipengaruhi oleh tremor/goncangan
gempabumi. Kunci dasarnya adalah bagaimana penentuan bahaya-bahaya gempabumi dengan baik, yang didapat dari estimasi potensi-potensi sumber
gempabumi. Dalam makalah ini, potensi goncangan tanah berdasarkan atas
syarat-syarat percepatan puncak tanah dari kajian/penelitian jarak jauh
gempabumi-gempabumi di Kalimantan Timur dan Sulawesi barat, dengan
mengikuti prosedur kajian probabilistik/kebolehajadian. Gempabumigempabumi
tersebut terjadi dalam waktu 50 tahun terakhir dengan radius 500
km. Berdasarkan nilai Percepatan Puncak Tanah tercatat sekitar 50% lebih
gempabumi-gempabumi Kalimantan Timur dan Sulawesi Barat yang telah
tercatat di Kalimantan Tengah, fungsi atenuasi Fukushima dan Yanaka (1992)
yang dipakai merupakan fungsi atenuasi yang berkaitan erat dengan
karakteristik tinggi wilayah tersebut. Perkiraan Percepatan Puncak Tanah
rencana untuk rancangan Bendungan Tailing/limbah padat tambang pada
batuan dipergunakan angka percepatan puncak 0,041 g (g = nilai gravitasi
bumi) dengan 10% kemungkinannnya terjadi dalam waktu 20 tahun, atau 0,103
g untuk tanah lunak. Dan 0,105 g dengan 10% kemungkinannnya terjadi dalam
waktu 1000 tahun pada batuan atau 0,261 g untuk tanah lunak. Bagaimanapun
juga, bahwa akhir-akhir ini terdapat gejala peningkatan tremor gempabumi,
seperti dengan telah terjadi Gempabumi Muarateweh tanggal 5 Juli 1996,
walaupun dilaporkan tidak terjadi kerusakan akan tetapi goncangan dirasakan
kuat.

Kata-kata kunci : percepatan tanah, goncangan tanah, fungsi atenuasi, rancangan tahan
gempabumi

»»  read more

PENDEKATAN GEOLOGI BAGI PENGEMBANGAN KAWASAN TUJUAN WISATA DI GUNUNG BATU, KECAMATAN LEMBANG, KABUPATEN BANDUNG

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

PENDEKATAN GEOLOGI BAGI
PENGEMBANGAN KAWASAN TUJUAN
WISATA DI GUNUNG BATU, KECAMATAN
LEMBANG, KABUPATEN BANDUNG

Yudi Satria Purnama,

Geological student ITB

Abstrak

Gunung Batu, Lembang telah sering digunakan sebagai tujuan perjalanan baik
oleh para mahasiswa geologi, peneliti geologi maupun oleh para anggota
masyarakat baik dari Kota Bandung maupun dari luar Kota Bandung.
Fenomena ini menggugah peneliti untuk mengkaji Geologi Gunung Batu yang
berperan sebagai faktor pendukung maupun pembatas untuk kemudian
dimanfaatkan sebagai pengembangan kawasan tujuan wisata. Hasil penelitian
menunjukkan bahwa atraksi yang terkandung berupa atraksi aktivitas rekreasi,
atraksi fenomena geologi (bentuk lahan Gunung Batu, singkapan, koluvial,
fenomena struktur geologi), atraksi hasil karya manusia bersifat geologi
(Stasiun Pengamatan Gempa dan galian batuan), dan atraksi budaya (makam
leluhur). Aktivitas utama yang dapat dilakukan di Gunung Batu adalah kegiatan
keilmuan geologi dengan tingkat kesulitan moderat, aktifitas outdoor
(pengamatan panorama (sightseeing) 360 o, berkemah, panjat tebing dengan
tingkat kesulitan menengah dan potensi aerosport) serta aktivitas spiritual. Nilai
yang terkandung di Gunung Batu adalah nilai aesthetic dan nilai rekreasi, nilai
scientific / research / pendidikan (berupa nilai geologi struktur), dan nilai
spiritual. Hasil penelitian juga menyimpulkan adanya faktor geologi yang
berperan sebagai pembatas yaitu : tingkat sensitivitas Gunung Batu pada
tingkat degradasi akibat penggalian dalam skala kecil (tingkat 7) maupun dalam
skala besar (tingkat 8); fenomena bencana geologi di kawasan berupa potensi
gerakan tanah dan potensi gerakan Patahan Lembang yang diakibatkan oleh
Sesar Cimandiri dan kegiatan magmatis Gunungapi Tangkubanparahu (?);
jatuhan piroklastik halus pada tingkat risiko rendah dari erupsi Gunungapi
Tangkubanparahu; serta zona bahaya yang terletak di tebing utara bagi
kegiatan menikmati panorama. Skala tingkat risiko faktor pembatas – tanpa
desain teknik – berada pada tingkat rendah hingga menengah. Diharapkan
hasil penelitian ini dapat dimanfaatkan sebagai data dasar untuk
menumbuhkembangkan fenomena mass tourism di daerah penelitian dengan
tujuan pada pengejaran dampak positif pariwisata baik dari segi ekonomi,
politik, sosio-kultural, maupun bidang lingkungan serta ekologi.

»»  read more

EXPERIMENTAL STUDY ON LOCALIZATION OF DEFORMATION (SHEAR ZONE) ON SATURATED SANDY SOILS IN RING SHEAR TEST

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

EXPERIMENTAL STUDY ON
LOCALIZATION OF DEFORMATION
(SHEAR ZONE) ON SATURATED
SANDY SOILS IN RING SHEAR TEST

Muhammad Wafid A N

Directorate of Geology and Mining Area Environmcnt

Abstract

Series of tests on saturated sandy soil under undrained and drained shearing
conditions, with various relative densities by means of ring shear apparatus
were carried out to investigate the shear zone development process The
macroscopic structural observations were conducted through “SOBO method”
by capturing the oven-dried samples using a camcorder/digital camera. This
observation revealed that for dense sand, the shear zone starts to develop at
failure and the thickness increases by progress of shear displacement. While for
loose sand no obvious developed shear zone at peak shear strength. In the
beginning of shear zone formation, the shape of the shear zone was refined
concavely with distinct undulating structure (secondary) which gradually
changed to become parallel when shear displacement proceed. Further
shearing the shape of shear zone was refined convexly with unrecognizable
shear surface. Another interesting phenomenon obtained by this study is that
when sandy soils has been sheared until reaching the steady state, the coarse
and the fine-particles (including the result of grain crushing) within the shear
zone became separated by segregation process. At this state, the core part
mainly consisted of coarse grain with very limited fine particles, while the fine
particles were accumulated at the bottom part of shear zone.

»»  read more

AIR TANAH PADA KARS DAN PERLINDUNGANNYA

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

AIR TANAH PADA KARS DAN
PERLINDUNGANNYA

Ir. Djaendi, Post. Grad. Dipl

Direktorat Tata Lingkungan Geologi dan Kawasan Pertambangan

Abstrak

Batu gamping merupakan bagian kecil dari batuan yang ada di Indonesia, akan
tetapi merupakan penyimpanan air tanah terbesar nomor tiga setelah batuan
volkanik dan batuan sedimen. Batu gamping secara alaminya bersifat kedap air
(tidak dapat meluluskan air), akan tetapi mempunyai kelemahan, bahwa batuan
ini mudah larut dalam air. Pada batuan ini mudah mengalami karstifikasi
dengan membentuk bentangan alam khas yang disebut kars. Proses ini
menyebabkan terbentuk porositas sekunder pada batuan gamping sebagai
tempat air tanah berada. Para ahli hidrogeologi selalu menggunakan fenomena
khas yang ada pada kars tersebut sebagai petunjuk dalam melakukan
penelitiannya terutama untuk mengetahui keterdapatan, penyebaran, dan
potensi air tanah pada batugamping. Fenomena tersebut seperti bentuk gua,
bentuk lembah, bentuk kelurusan morfologi batuan, sampai kepola keberadaan
tetumbuhan, semuanya mengidentifikasikan kemungkinan terbentuk dan
terdapatnya air tanah.

Kondisi air tanah pada batuan kars sangat rumit dan khas, tidak bisa
disamakan dengan kondisi air tanah pada batuan yang mempunyai lubang
bukaan antar butir dan celahan jenis lainnya. Air di kawasan kars bergerak
melalui sistem retakan, celahan atau gua, sehingga membentuk aliran melalu
saluran (konduit), dengan medianya akan bersifat heterogen. Aliran air tanah
akan bergerak lebih cenderung bersifat turbelen atau berputar (tidak lunak).
Dengan demikian air yang mengalir melalui lorong-lorong gua dapat dianggap
sebagai akuifer utama yang berbentuk sungai bawah tanah sedangkan yang
mengalir melalui celah atau retakan batuan sebagai cabangnya. Jika ditinjau
dari tingkatan karstifikasi pada batugamping, dapat dikelompokan menjadi tiga
tingkat, yaitu kars berkembang baik, kars berkembang sedang, dan batuan
karbonat nonkars. Kars berkembang baik pada umumnya dijumpai berada di
bagian atas dari daerah kars, dengan bukaan cukup baik dan berfungsi sebagai
daerah meresapnya air menjadi air tanah. Di bagian lebih dalam kars terdapat
akuifer yang disusun oleh jaringan celah, retakan, dan gua yang saling
berhubungan. Akuifer ini membentuk subsistem tersendiri yang memiliki
kecepatan aliran mulai dari lambat sampai cepat tergantung porositas sekunder
yang ada. Keberadaan subsistem ini sangat menentukan dalam terbentuk sifat dan pola aliran air tanah, selain menjadi faktor penentu sistem hidrolika kars
yang heterogen. Di bagian paling bawah akuifer kars dialasi batuan karbonat
nonkars yaitu batu karbonat yang belum mengalami karstifikasi dan belum
memiliki porositas sekunder dan kondisi ini hanya akan dijumpai jika
batukarbonat cukup tebal. Jika dirunut keberadaan air tanah pada kars terdiri
dari bagian paling atas merupakan zona kering, kemudian zona peralihan, zona
jenuh air, dan paling bawah lapisan kedap air.

Penyebaran potensi air tanah pada batuan kars tidak merata dan hanya berada
di daerah-daerah yang sudah mengalami karstifikasi yang sempit, sedangkan di
daerah sampingnya merupakan daerah kering. Keberadaan air tanah kars tidak
bisa lepas dari siklus hidrologi yang berlangsung di alam. Keterdapatannya
sangat dipengaruhi lingkungan sekitar seperti iklim, penggunaan lahan, dan
tutupan lahan. Sehubungan dengan itu dasar pertimbangan bila akan dilakukan
perubahan pemanfaatan lahan di daerah kars, harus dilandasi pemahan
perilaku air tanah pada suatu kawasan kars, terutama mengenai keterdapatan,
penyebaran, dan pengaliran air tanah, sehingga dapat memperkecil dampak
negatif yang akan timbul terhadap lingkungan terutama pada kondisi air tanah
itu sendiri. Upaya-upaya yang perlu dilakukan terhadap perlindungan air tanah
terutama dari kegiatan penambangan, perubahan daerah resapan,
pengambilan air tanah, dan penurapan mata air. Semua kegiatan tersebut
merupakan usaha-usaha dalam kegiatan konservasi air tanah di daerah kars
yang harus dilakukan.

»»  read more

THE LEMBANG FAULT

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

THE LEMBANG FAULT

Danny H. Natawidjaja and Djedi S. Widarto

Research Center for Geotechnology-LIPI

Abstract

Lembang fault runs east-west in the northern part of Bandung. This fault zone
is clearly seen along its ~25 km section, indicated by a lineament of a marching
hills, from the area east of Maribaya resort to the Cisarua-Cimahi region in the
west. The tectonic morphologies on and around the fault line indicates that this
fault has been active in the Quaternary through the Holocene periods, and
probably until recent. The length of the fault implies that this fault may be able
to produce an earthquake with a magnitude of 6 to 7. The fault zone that runs
through a fairly developed and populated region, and is located just about 15
km north of the highly populated city of Bandung urges to be seriously taken
into account for hazard mitigations and for a development planning of the city.
We perform geological and morpho-tectonics analyses as well as reviewing
previous geological and geophysical data in order to investigate the history,
kinematics and activity of the Lembang fault.

Abstrak

Patahan Lembang membentang dari timur ke barat di kawasan sebelah Utara
Bandung. Jalur patahan ini jelas terlihat di sepanjang ~25 km, yang dicirikan
oleh kelurusan untaian bukit-bukit, mulai dari daerah sebelah timur tempat
pariwisata Maribaya sampai ke daerah Cisarua-Cimahi di baratnya.
Kenampakan tektonik morfologi pada dan sekitar jalur patahan
mengindikasikan bahwa patahan ini bergerak aktif pada Zaman Kuarter dan
kemungkinan besar aktivitasnya masih terus berlangsung sampai Zaman
Holosen, bahkan sampai sekarang. Dari panjang patahan dapat diperkirakan
bahwa patahan ini berpotensi untuk menghasilkan gempa berkekuatan antara 6
sampai dengan 7 skala Richter. Letak patahan yang melewati wilayah yang
sudah cukup berkembang dan padat, dan juga hanya sekitar 15 km dari Kota
Bandung menjadikan zona patahan ini harus serius diperhitungkan dalam
usaha mitigasi bencana dan dalam rencana pengembangan kota. Kami
melakukan analisa geologi dan morfo-tektonik dari patahan, di samping juga
mengevaluasi data geologi dan geofisika terdahulu dengan tujuan untuk
meneliti sejarah, kinematika, dan keaktifan dari Patahan Lembang.

»»  read more

INVESTIGATION OF SUSPENDED PARTICULATE MATTER USING MODIS AQUA IMAGES

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

INVESTIGATION OF SUSPENDED
PARTICULATE MATTER USING MODIS
AQUA IMAGES

(MEMANTAU SEBARAN SEDIMEN TERLARUT
DENGAN CITRA MODIS AQUA)

Afiat Anugrahadia and Nani Hendiartib

aDepartment of Geological Engineering /Center of Mineral Resources and Marine Coastal

Management Studies, FTM, University of Trisakti, Kyai Tapa 1, Jakarta 11440. Email:

afiat_anu@yaho.com

bAgency for the Assessment and Application of Technology, M.H. Thamrin 8, Jakarta

10340. Email : hendiarti@webmail.bppt.go.id

Abstract

Geological processes which are continuously occured for long time are
agradation as a development characteristic and degradation as destructive.
This process has been continued until now. Agradation is not always
advantage for human living but often disadvantage esspecially on the coastal
and marine region. For example superviciality of downstreams and harbour, and
making turbid, that are disadvantage of recent sedimentation.Suspended
sediment is inorganic matter originated from coastal discharge of river, wetland,
coastal and bottom sea abration, and than human activity. Coastal
discharge distributed by wind and surface current. The surface pattern of the
discharged water can be recognized from the satellite ocean color images such
as SeaWiFS dan MODIS Aqua. The discharged water which is dominated by
inorganic particulate matter can be identified by increasing the energy values
in the long visible wavelength range. This wavelength range is in between
510nm and 550nm. The results obtained from the investigation of suspended
particulate matter using ocean color MODIS Aqua images show that high
concentration of organic matter is founded in East Sumatra of Java Sea and
spread to Seribu Islands in North of West Java forced by the west winds during
the second week of Mei 2004. The distribution of the material was observed
until 3.5 miles in north of Jakarta bay and its spread also along north Java
coast. This fenomena is occured in the period of thousand fish killed in this
region.

The conclusion is that remote sensing can be used for mapping coastal
discharge in spatial with sufficiently and continuously. Moreover, spectral
analysis can produced the information of the composition and concentration of
organic and inorganic matter in the waters near surface. These information is
useful for monitoring the environmental changes and for early warning system
of environment disarter.

»»  read more

SUSPENSION AND SEDIMENT SURROUNDING OF NORTHERN PART WATER OF SULAWESI UTARA

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

SUSPENSION AND SEDIMENT

SURROUNDING OF NORTHERN PART

WATER OF SULAWESI UTARA

Helfinalis

Research Center For Oceanography LIPI

Abstract

The beach of Kwandang bay generally found mangrove, muddy sand and
breccias (rose color), schist In the East and Northwest. The wide of the beach
slope more less 25 meters with angel 3-5º .The coastal plain is very narrow and
direct connected to the hilly. On the Hill generally have red clay and breccias
with black color. In the Gobba found coarse sand with 1-2 meters depth. The
corai reef more less 100 metre wide with 1-4 meters depth and the bay with 4050
meters depth and content of greenish grey mud. As long as Menado Bay
generally has in dam, except in the eastern part. Malalayang beaches content
of coarse sand with jetty in T form and for protected the beaches from the
waves. The reclamation of the beach saw in the East Menado bay until hundred
meters to the east of the Menado port and in front of areas putted the breccias
for protected the beach from erosion.

The suspension value on the surface water (2 meters depth) more higher
compared with in the middle and bottom. In general, the all suspension value
still below the tolerance limit of KLH < 70 mgr/l. On the surface until 40 cm thick
of sea sand around Bangkit and Bunaken Islands. On the others of surface
seafloor found mixing between gravel, sand, silt and mud.

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THE IMPACT OF MERAPI VOLCANICLASTIC DEPOSITIONS INTO YOGYAKARTA ENVIRONMENTAL DEVELOPMENTS

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

THE IMPACT OF MERAPI
VOLCANICLASTIC DEPOSITIONS INTO
YOGYAKARTA ENVIRONMENTAL
DEVELOPMENTS

Sri Mulyaningsih1, Sampurno2, Yahdi Zaim2 and D.J. Puradimaja2

1Dept. of Geology ISTA and PhD student at Dept. of Geology ITB
2Dept. of Geology ITB

Abstract

Yogyakarta is one of the most densely populated provinces in Indonesia. Very
dynamic geological condition have been developed since the presence of
Merapi Volcano, northern the city. The developing environmental geology are
realizing within flat landscape of Yogyakarta, lens system aquifer geometry and
very abundant resources such rock fragments and sand as building materials,
fertile soils and ground water. The phenomenon was implementing into its
cultivation styles in the building dispersion and their shapes up to a few
centuries ago.

Key words: Merapi, Volcaniclastic, depositions, geology, environment and
development

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IDENTIFICATION OF PYROCLASTIC DEPOSIT TYPES (FLOWS, SURGES AND FALLS) AT MERAPI VOLCANO AND FACTORS INFLUENCE THEIR DISTRIBUTION

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

IDENTIFICATION OF PYROCLASTIC
DEPOSIT TYPES (FLOWS, SURGES AND
FALLS) AT MERAPI VOLCANO AND
FACTORS INFLUENCE THEIR
DISTRIBUTION

Supriyati D. Andreastuti

Volcano Technology Research Center (BPPTK),
Directorate of Volcanology and Geological Hazard Mitigation

Abstract

Identification of pyroclastic deposit types (pyroclastic flow, surge and fall) was
made in the field using physical characteristics (internal structure, thickness,
colour, lithology and mineralogy) and analysed further by grain size analyses.
Pyroclastic flow deposits are composed of ash to block sized material, and are
depleted in ash (less than 2 %). Pyroclastic surge deposits are dominated by
ash material, range from fine to coarse ash, and are fine-ash-enriched (up to 17
%). Pyroclastic fall deposits are characterised by a wide range of grain-sizes
from fine ash to lapilli and are generally depleted in fine ash.

Distribution of these deposits was influenced by topographic condition
(roughness and orientation) and grain size. In pyroclastic surge, the more
irregular the morphology the shorter the travel distance from the source.
Perpendicular topography passed by the surge also result in shorter distance
than the parallel one. Pattern of prevailing wind and strength of wind condition
affects the shape of the dispersal and distribution pattern of fine grained
material of pyroclastic fall leading to climate condition of eruption can be
suggested.

Geo-Environment & Hazard

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SISTEM AKUIFER KETERKAITANNYA ANTARA MORFOLOGI DAN KETERDAPATAN AIR TANAH DI DAERAH PEKANBARU, PELIAHARI DAN BENGKALIS, PROPINSI RIAU.

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

SISTEM AKUIFER KETERKAITANNYA
ANTARA MORFOLOGI DAN
KETERDAPATAN AIR TANAH DI DAERAH
PEKANBARU, PELIAHARI DAN
BENGKALIS, PROPINSI RIAU.

Robi S Hidayat

Abstrak

Daerah pemetaan hidrogeologi lembar 0816 Pekanbaru. Secara geografis
terletak pada garis 100° 30’ – 102° 00’ Bujur Timur dan garis 00° 00’ - 01° 00’
Lintang Selatan. Sedangkan secara admunistrasi pemerintah daerah pemetaan
ini terletak di Provinsi Riau meliputi wilayah Kota Pekanbaru, sebagian
Kabupaten (Kab) kampar, Kab. Palelawan, dan Kab. Bengkalis. Hampir
sebagian besar penduduk yang tinggal di daerah pemetaan, memenuhi
kebutuhan air bersih dari budidaya sendiri, yakni dari air tanah melalui sumur
gali, mata air, maupun air sungai. Namun secara umum dapat dikatakan bahwa
peranan air tanah dalam pemenuhan kebutuhan air bersih bagi penduduk,
masih sangat dominan.

Morfologi daerab pemetaan dapat dibedakan atas tiga satuan, yakni satuan
morfologi dataran, perbukitan rendah, dan perbukitan tinggi. Setiap satuan
tersebut mempunyai karakteristik geomorfologi tersendiri, yang memberikan
kontrol yang berbeda terhadap keterdapatan air tanahnya. Lithologi akuifer
daerah penyelidikan berdasarkan jenis kesarangannya dapat dibedakan
menjadi 3 (tiga) sistem yaitu :

1. Sistem akuifer melalui ruang atau butir
2. Sistem akuifer melalui celahan, dan ruang antar butir
3. Sistem akuifer melalui rekahan
Setiap sistem tersebut tersusun oleh berbagai jenis litologi dengan kelulusan
yang berbeda-beda. Aluvium dan sedimen klastik yang berumur kuarter
menunjukkan kelulusan sedang sampai tinggi, sedangkan campuran batuan
beku dengan batuan malihan umunya berkelulusan rendah sampai sangat
rendah. Berdasarkan keterkaitan antar morfologi dan keterdapatan air
tanahnya. daerah pemetaan dapat dibedakan atas dua mandala air tanah
(groundwater province), yakni mandala air tanah dataran dan perbukitan.

Setiap mandala air tanah ini menunjukkan ciri hidrogeologi yang berbeda.
Setempat keterdapatan air tanah di sebagian mandala air tanah dataran
mempunyai arti yang penting ditinjau dari segi produktivitas akuifernya,
digolongkan sebagai akuifer tidak tertekan dan semi tertekan hingga tertekan
yang benlapis-lapis (multy layers), sedangkan pada mandala air tanah
perbukitan tergolong sebagai akuifer tidak terekan yang kurang produktif, air
tanah dengan jumlah terbatas dijumpai di bagian lembah dan zone pelapukan
batuan. Angka keterusan (T) dari kelompok akuifer endapan aluvium umumnya
termasuk sedang hingga tinggi. Debit sumur lebih besar dan 5 1/det, muka air
tanah sekitar 2,0 m di bawah muka tanah setempat. Pemunculan mata air
terutama dijumpai di mandala air tanah perbukitan, yakni di daerah Merangin,
Rantau Beringin, dan Banjar Salero dengan debit kurang dan 1 l/det.

Komposisi kimia air tanah didominasi oleh unsur magnesium bikarbonat,
sodium klorida, sodium bikarbonat, sodium nitrat, dan calsium bikarbonat. Mutu
air tanah di daerah pemetaan umumnya memenuhi persyaratan air minum
walaupun tingkat keasamannya rendah, serta air tanah didaerah pemetaan ini
tergolong layak untuk keperluan pertanian. Meskipun penelitian hidrogeologi
yang bersifat kuantitatif masih diperlukan uji akuifer, namun beberapa daerah
yang prospek pengembangan dan pemanfaatan sumberdaya air tanahnya
paling menjanjikan yaitu daerah dataran antara lain daerah dataran Pekanbaru,
Rumbai, Tanab Merah, dan Minas, yaitu pada akuifer endapan rawa terdiri atas
pasir dan kerikil.

Geo-Environment & Hazard

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LANDSLIDE IN KEBUMEN TERITORY SOUTH PART CENTRAL JAVA

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Oct 2004, Bandung

LANDSLIDE IN KEBUMEN TERITORY
SOUTH PART CENTRAL JAVA

Eko Soebowo, Herryal Z. Anwar, Dwikorita Karnawati

Pusat Penelitian Geoteknologi – LIPI

Abstract

Kebumen Region and others Southern Part of Central Java have a long history
on landslide hazard occurrences. Landslides in this area are influenced by the
litological condition, morphology, structure, hidrology, rainfall and others factor.
Therefore, landslides potential area information is primarily important to design
the effective mitigation system. Engineering geological study which has been
done in this area indicate that landslides distribution concentrate mainly at
Ayah-Karangbolong-Alihan-Rowokele area, at litological unit of weathered
volcanic breccia with structures zone at this area, and at contact zone between
this rocks and sedimentary rock. Whereas at Tugu, Panusupan, Sambeng,
North Karangsambung at litology marly clay and tuffaceous sandstone and
phyllite. The landslide tipical is generally debris flow, slump and creeping. The
result of this study are useful to design the mitigation strategy of landslide
hazard and also may be used for land conservation requirement, particularly to
develop a Master Plan of this area.

Abstrak

Wilayah Kabupaten Kebumen, Jawa Tengah Bagian selatan mempunyai
sejarah yang panjang akan permasalahan gerakan tanah. Dalam upaya untuk
memitigasi gerakan tanah di wilayah ini diperlukan informasi sebaran bahaya
gerakan tanah. Mengingat peristiwa gerakan tanah disuatu daerah sangat
dipengaruhi oleh kondisi litologi, morfologi, struktur, hidrologi, curah hujan dan
faktor lainnya. Berdasarkan hasil penelitian menunjukkan bahwa sebaran
kejadian gerakan tanah/longsoran, terkonsentrasi terutama di daerah-daerah
Ayah – Karangbolong – Alihan – Rowokele pada litologi satuan breksi volkanik
yang lapuk dengan zona struktur patahan, dan pada kontak satuan batuan
tersebut dengan satuan sedimen. Sedangkan di daerah Tugu, Panusupan,
Sambeng, utara Karangsambung pada litologi satuan lempung napalan dan
batupasir tufaan dan filit. Kejadian longsoran tersebut mencerminkan tipe bahan
rombakan, runtuhan dan rayapan. Hasil tersebut dapat dimanfaatkan untuk
strategi mitigasi bencana geologi longsoran dan dapat digunakan sebagai
perlindungan lingkungan terhadap lahan-lahan yang akan dikembangkan
khususnya dalam penataan ruang dan pengembangan wilayah di daerah ini.

Geo-Environment & Hazard

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SEISMIC HAZARD ASSESSMENT: In the Case Study of Minesite Area-Central Kalimantan Engkon K.Kertapati

Convention Bandung 2004 (CB2004)
The 33rd Annual Convention & Exhibition 2004

Indonesian Association of Geologist
Horizon Hotel, 29-30 Nov, 1 Dec 2004, Bandung

SEISMIC HAZARD ASSESSMENT:
In the Case Study of Minesite Area-Central
Kalimantan

Engkon K.Kertapati

Geological Research and Development Centre

Abstract
The low-seismicity Central Kalimantan has never experienced any earthquake damage.
Thus, earthquake-resistant design has not been specifically required in the building codes.
However, it has been realized that urban and mine areas located rather distantly from
earthquake sources may also be affected by tremors. The key is basically determined by how
well seismic hazards derived from seismic potency can be estimated. In this paper, the
potential ground motion in terms of the peak ground accelerations ( PGAs) due to long –
distance East Kalimantan and West Sulawesi earthquakes ( far field earthquake ) is
investigate, following a probabilistic seismic hazard assessment approach. Earthquakes that
have occurred in radius of 500 km ( far field ) in the last 50 year are used. Based on the
PGAs of more than 50 % East Kalimantan and West Sulawesi earthquakes recorded in
Central Kalimantan, the attenuation relationship of Fukushima and Tanaka ( 1992 ) is found
to correlate well with the high-rate attenuation characteristic of the region. The predicted
design basis PGA for Tailings Dam , i.e. PGA with 10 % probability of being exceeded in a
50-year exposure time, on rock out-crops site is 0.041 g ( g = gravity value ), or 0.103 g on
soft soil. And 0.105 g with 10 % probability of being exceeded in a 1000 year exposure time
on rock out-crops or 0.261 g for soft soil. However, the increasing number of felt tremors in
recent years demonstrates such as: Muarateweh Earthquake, which occurred on July 05,
1996, that although no significant damage was report, the earthquake was strongly felt.

Keywords: ground acceleration, ground-motion, attenuation function, earthquakeresistant
design

Abstrak
Kalimantan Tengah dengan tingkat kegempaan yang rendah, tidak pernah mengalami
gempabumi merusaka. Oleh karena itu, rancangan bangunan tahan gempa, secara khusus
tidak diperlukan dalam kode bangunan. Walaupun demikian, perkotaan dan daerah-daerah
penambangan yang agak berjarak dari sumber-sumber gempabumi dapat dipengaruhi oleh
tremor / goncangan gempabumi. Kunci dasarnya adalah bagaimana penentuan bahayabahaya
gempabumi dengan baik, yang didapat dari estimasi potenti-potensi sumber
gempabumi. Dalam makalah ini, potensi goncangan tanah berdasarkan atas syarat-syarat
percepatan puncak tanah dari kajian / penelitian jarak jauh gempabumi-gempabumi di
Kalimantan timur dan Sulawesi barat, dengan mengikuti prosedur kajian probabilistik /
kebolehjadian. Gempabumi-gempabumi tersebut terjadi dalam waktu 50 tahun terakhir
dengan radius 500 km. Berdasarkan nilai Percepatan Puncak Tanah tercatat sekitar 50 %
lebih gempabumi-gempabumi di Kalimntan Timur dan Sulawesi Barat tercatat di Kalimantan
Tengah., fungsi atenuasi Fukushima dan Tanaka ( 1992 ) yang dipakai merupakan fungsi
atenuasi yang berkaitan erat dengan karakteristik gempabumi wilayah tersebut. Perkiraan
Percepatan Puncak Tanah Rencana untuk rancangan Bendungan Tailing / limbah padat
tambang pada batuan dipergunakan angka percepatan puncak 0.041 g ( g = nilai gravitasi
bumi ) dengan 10 % kemungkinannya terjadi dalam waktu 50 tahun, atau 0.103 g untuk tanah
lunak, dan 0.105 g dengan 10 % kemungkinannya terjadi dalam waktu 1000 tahun pada batuan atau 0.261 g untuk tanah lunak. Bagaimanapun juga, bahwa akhiir-akhir ini terdapat
gejala peningkatan tremor gempabumi, seperti dengan telah terjadi Gempabumi Muarateweh
tanggal, 5 Juli 1996 walaupun dilaporkan tidak terjadi kerusakan akan tetapi goncangan
dirasakan kuat.

Kata-kata kunci: percepatan tanah, goncangan tanah, fungsi atenuasi, rancangan tahan
gempabumi.

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