Geothermal System of the Dieng-Batur Volcanic Complex

This paper is mainly concerned with the evaluation of reports on geophysical and geochemical surveys made by Group Seven Inc. and Truesdell in the Dieng Mountains under contract with US-AID and on behalf of the Directorate General for Power and Electricity and the Indonesian Geological Survey and partly also with the author's own field observation on geothermy in the Dieng Mountains in Central Java. All the accumulated data lead to the conclusion that the geothermal system of eastern Dieng originated through the intersection of two major fracture zones. The high chloride content found in various streams gives good reason to accept that the geothermal system of the Dieng Mountains is a system of hot water and steam rather than a system of dry steam only. The hot springs in the Dieng Mountains might represent surface manifestation of a deep, neutral, hot water "reservoir". The distribution of geo-electric anomaly which resulted from two dipole mapping surveys delineated a belt of anomalously low resistivity in the eastern Dieng Mountains in which there are three areas of very low resistivity indicating systems of up-welling thermal water. These systems might be connected at great depth. The area with low resistivity anomaly might indicate a reservoir having a volume of 5 to 6 cubic kilometers at depth of 2 kilometers. An estimate based on geophysical data suggests that a power production rate of 200 megawatts could be supported for 25 years, or of 100 megawatts for 50 years. Based on all those data an exploratory deep drilling work is recommended which is due to start in June 1971.

The Origin of Several Pyroclastic Plateaux in the Padang Highlands (Central Sumatra) (Preliminary Paper)

Abstract. Several pyroclastic plateaux are known in the Padang Highlands. Westerveld (1952) suggested that those rhyolitic volcanics are sheetlike deposits of paroxysmal fissure eruption similar to the incandescent clouds of the Katmai type. Field observation, however, suggested that at least the pyroclastic plateau of Bukit Tinggi might as well be the result of an air borne tuff deposition which originated from a gigantic outburst of the Manindjau volcano prior to its caldera formation. The tuff plateau of Bukit Tinggi, as revealed by the exposures in Ngarai SiAnok, is neither layered nor welded and could not be deposited in water either. The landscape between Matur and Bukit Tinggi gives the impression as if ducoed by tuff from the air.  Ringkasan. Beberapa daratan jang terbentuk dari bahan pyroklastik dikenal di Daratan Tinggi Padang. Menurut Westerveld (1952) dataran2 tinggi tersebut jang terdiri dari batuan volkanik bersifat rhyolitik merupakan endapan pyroklastik terdiri dari lembaran2 (sheetlike) dan dihasilkan oleh suatu erupsi rekahan jang sama sifatnja dengan endapan awan panas dari Gunung Katmai di Alaska. Penelitian lapangan, sebaliknja, lebih menundjukkan bahwa dataran2 tinggi tadi, terutama Dataran pyroklastik Bukit Tinggi, mungkin sekali berupa endapan pyroklastik dari udara jang dikeluarkan oleh letusan raksasa Gunung Manindjau pada saat2 mendjelang ambruknja gunung tersebut untuk membentuk kaldera Danau jang besar itu. Dataran Tinggi tufa Bukit Tinggi, sebagaimana terlihat pada singkapan2 jang djelas di Ngarai Si Anok, tidak memperlihatkan perlapisan dan djuga tidak memperlihatkan "welding". Endapan tufa tersebut djuga tidak mungkin diendapkan diair. Bentang alam antara Matur dan Bukit Tinggi memberi kesan se-akan2 di-"duco" dari udara oleh tufa

Geothermy and its Future in Indonesia

Abstract. The basic concept of a commercial steamfield is discussed and defined in this paper. Based on this discussion potential areas are indicated in a map. It is found that not less 24 geotherrnal areas are prospectable. However, it is found that very little is known about the exact potential of Indonesia in the field of geothermy. Anticipating the rising demand in electricity within the context of the broader industrialisation program of Indonesia and the limitation of its fossil fuel reserve, it is suggested that all possibilities for utilising different kinds of energy, including geothermy should be explored as far as possible. Ringkasan. Konsep dasar dari suatu medan uap alam komersil diperbincangkan dan didefinisikan. Berdasarkan pada diskusi tersebut daerah-derah dengan potensi geothermy dicantumkan ke dalam peta. Ternyata bahwa tak kurang dari 24 medan hyperthermal tersebar di seluruh wilayah Indonesia yang berkemungkinan untuk dapat dieksplorasikan lebih lanjut. Saying sekali bahwa sangat sedikit yang diketahui mengenai potensi Indonesia sesuangguhnya dalam bidang ini. Menghadapi permintaan tenaga listrik yang semakin menanjak dalam rangka pengembangan program industrialisasi Indonesia, dan terbatasnya persediaan bahan bakar fossil, pengarang menganjurkan agar semua segi dan kemungkinan pemanfaatan segala macam sumber energi , termasuk geothermy, dijajaki sejauh mungkin

Tondano Pyroclastic

Abstract. Recent A recent investigation into the volcanic geology of Minahasa revealed the existence and distribution of pyroclastic flow sheets of which origin and mode of emplacement are yet to be solved. These pyroclastic flow sheets are found covering nearly whole Minahasa. It consists of loose to dense tuff or tuffaceous material, containing angular, to subangular and rounded pumice fragments measuring from a few mm to 15-20 mm across, showing several cycles of deposition. Welding is only detected at one spot and very limited. Quartz fragments are common but not abundant. Along the lake of tondano those pyroclastics form terraces ranging in height from 1.5 to 20 m, whereas farther away along the North and the South east these pyroclastic sheets form typical soft undulating landscapes. Most probably these pyroclastics originated from fissure like eruptions in a longitudinal riftvalley on the crest of the Minahasa geanticline bordered to the SE by the slightly crescentic Lembean scarp, and to the NW by a row of young volcanoes. Some of the pyroclastics might have deposited aerially some showed some indication of flowage after deposition. In Central and East Minahasa most part of these pyroclastic sheets are covered by young and recently produced volcanics of andesitic composition. The magnitude of this deposit makes it necessary to be mapped as a separate unit and the regional mapping team of the Geological Survey of Indonesia should pay considerable attention to their presence and geologic importance, since, next to Toba this pyroclastic deposit is one having the largest surface distributionRingkasan. Suatu penelitian pendahuluan di daerah Minahasa baru-baru ini menemukan penyebaran suatu batuan pyroklastika secara luas sekali. Batuan ini dapat digolongkan sebagai "pyroclastic flow sheets" sedangkan asal usul endapan ini secara terperinci belum dapat diketahui dengan jelas. Endapan ini terdiri dari batuan tufa padat maupun tufa lepas dengan fragmen batu apung berbentuk angular ataupun bundar dengan diameter berkisar antara 15 hingga 20 cm. Endapan tersebut memperlihatkan ciri-ciri pengendapan bersiklus. Gejala "welding" hanya diketemukan pada satu tempat dan itupun secara sangat terbatas. Fragmen mineral kwarsa juga tampak tetapi tidak terlalu banyak. Disekitar danau Tondano, disebelah Barat Daya, endapan tadi membentuk teras-teras dengan ketinggian 15-20 meter sedangkan jauh di pantai Utara dan Selatan endapan tadi membentuk bentang alam ber-undulasi yang lemah. Besar kemungkinan endapan tadi berasal dari letusan-letusan yang terdapat pada puncak geantiklin Minahasa yang dibatasi pada sebelah Timur oleh "Lembean Scarp", sedangkan disebelah Barat ia dibatasi oleh deratan kerucut gunung-gunung berapi muda. Sebagian dari endapan pyroklastik tadi mungkin diendapkan dari udara, sebagian mengalami proses aliran sesudah diendapkan dari udara. Di Minahasa Tengah dan Minahasa Timur sebagian dari endapan pyroklastik tadi ditutupi oleh bahan-bahan volkanik berkomposisi andesit. Karena endapan tadi sangat luas, endapan-endapan tadi mungkin perlu dipetakan sebagai satuan terpisah, oleh karena itu perlu diperhatikan oleh team pemeta Direktorat Geologi. Sesudah Toba mungkin endapan pyroklastik Tondano adalah endapan terbesar di Indonesia

Mekainika Aliran Air tanah Pada Akifer Karst:Melalui saluran Fraktal

In mathematical modeling of groundwater flow mechanics through conduit system, generally the cross sectional area of the conduit is assumed as a circular disk. In the matter of fact, the real cross sectional area of a karst conduit is non_ circular, even tend to be irregular. This irregularity causes the karst conduit difficult to be defined as euclidean geometry, but more appropriately presupposed as fractal geometry. Therefore, dealing with groundwater in karstic aquifer, some flow mechanics equations such as Bernoulli equation, need to be reviewd. This paper tries to develop some existing ,flow mechanics equations to make those acomodatable for fractal geometry. It is expected that the more acurate results will be acquired

Menuju kelestarian lingkungan hidup

xiii, 245 p.; 20 cm

Dialog teknologi dan industri : pemacuan teknologi menuju terbentuknya industri nasional yang kuat dan berdaya saing tinggi

ix, 291 p. : il.; 25 cm

MENUJU KELESTARIAN HIDUP

Buku ini membantu pembaca untuk melihat interelasi dari 5 masalah pokok tata lingkungan; dinamika kependudukan, pengembangan SDA dan energi, pertumbuhan ekonomi, perkembangan ilmu pengetahuan dan teknologi dan benturan terhadap tata lingkungan. Pembaca mendapat suatu kenyataan bahwa masalah tata lingkungan di Indonesia sebenarnya adalah akibat kemiskinan masyarakat. Dan karena itu masalah pelestarian lingkungan di Indonesia adalah masalah yang sangat relevan dalam pembangunan nasional.xiii.; 230hlm.; illus;14 x 21 c

Menuju Kelestarian Lingkungan Hidup

xiii,245 hal,;ill,;21 c

Physico-Chemical Analysis of Mineral Paragenesisin Zoned Skarns

1)    Proses matematis jang merupakan proses dimana terlibat perubahan komposisi kimia setjara keseluruhan (bulk composition) dari kelompok2 mineral tertentu (mineral assemblage) ternjata dapat diterangkan dengan prinsip2 "phaserule" dari Gibs dan ada hubungannja dengan thermodynamica2)    Proses metasomatis mengeluarkan mineral jang karakteristik dan stabil di mana konsep dari "mineral facies" dapat dipakai.