> Coba kita tengok bagaimana jurnal-jurnal ilmiah luar negeri mengulas LUSI > ini. Saya mengamati beberapa, dan ternyata semua sama yaitu bahwa mereka > hanya sepakat bahwa Lusi adalah "mud volcano eruption" Apa penyebab > erupsinya ? Gempakah, pengeboran Lapindokah ? Tak tahu. Besar kemungkinan > dua-duanya. Sebuah jurnal menyebutkan juga gejala geotermal. Di bawah ini > adalah salah satunya. > > Salam, > Awang > > > Mud volcano floods Java > > > Disaster-plagued Indonesian island faces new threat. > > by Richard Van Noorden > <http://www.nature.com/news> [EMAIL PROTECTED] > What Has Happened ? > For 3 months a sea of hot mud has been gushing from the ground in > Sidoarjo, East Java, 35 kilometres south of Indonesia's second largest > city, Surabaya. The steaming mud pool is growing at an estimated 50,000 > cubic metres a day, accompanied by hydrogen sulphide gas, and now > reportedly covers more than 25 square kilometres. The flow has not yet > been stopped; thousands of people have lost their homes. > > How bizarre... has this sort of disaster happened before? > > The Sidoarjo disaster is an example of a 'mud volcano'. ________________________________________________________________________
Mud and gas > accumulates when sea sediments are trapped in subduction zones, where one > tectonic plate slides under another, and can erupt out of volcanic cones > or simply from a crack in the ground. Kang Awang. Re- keterangan diatas , bagaimana mengaplikasikan - nya dalam kasus Sidoarjo ? Apakah posisi subduction zone dan saat sedimentasi mendukung pendapat diatas ? Kelihatannya kita harus melihat dan belajar dari kejadian kejadian di - region lain untuk menambah data sebelum suatu kesimpulan final dicapai. Hal ini penting SEKALI karena akan menyangkut suatu keputusan Pengadilan dalam banyak "pengaduan dari masyarakat". Si- Abah ________________________________________________________________________ Mud volcanoes have burst on every > continent, but are abundant in the South Caspian region (offshore and > onshore Azerbaijan) and offshore Indonesia in the East Java Basin. > But the Sidoarjo mud volcano is rather unusual. It's huge. And, says Sam > Rice, a geologist at the University of Cambridge, UK, reports of the mud > eruption suggest that it is a hybrid between typical mud volcanoes and > hydrothermal vents. The mud is of an unusually high temperature (60 °C) > and contains enormously high concentrations of hydrogen sulphide gas. This > suggests that some kind of volcanic, hydrothermal activity is going on at > the same time. > > What creates the conditions for a mud volcano? > > Achim Kopf, a geologist from the University of Bremen, Germany, who has > studied mud volcanoes extensively, explains that marine sediment can be > scraped off an oceanic tectonic plate as it slides underneath a > continental plate. If the sediment accumulates rapidly and water is > trapped in its pores, this can stop the sediment being cemented by > pressure. The resulting reservoir of mud can be trapped underground. In > the case of the East Java mud flow, the mud is thought to have come from a > reservoir some 2.7 kilometres below the Earth's surface. > > And what triggers an eruption? > > A number of things can create a crack that allows trapped mud to bubble to > the surface; particularly earthquakes and drilling. > > And in Java specifically? > > In Java both of these things have happened recently. The oil and gas > exploration company PT Lapindo Brantas is drilling in the area, and the > gas and hot mud first spewed from the company's drilling rig on 28 May. > Geologist Georg Delisle of the Federal Institute for Geosciences and > Natural Resources (BGR), Hannover, Germany, explains that the drilling > apparently penetrated into the liquid sediment and created a connection > back to the surface. The pressure then squeezed up the mud, like > toothpaste from a tube. But it is likely that other connections were made > to the surface, he adds not just through the drilling pipe because > attempts to pump concrete into the pipe to block the flow of mud have > failed. > On 27 May an earthquake struck and devastated Yogyakarta on Java, and this > too could have cracked the ground, potentially helping to release the mud. > But the quake's epicentre was some 300 kilometres away from the mud > volcano (making it only 2 on the Richter scale in that area). > The issue of what, exactly, caused this disaster is highly politically > charged. It is still under investigation by police, the government and > international experts. > > Just how big is the eruption? > > According to many geological experts, the scale of this mud volcano is > unprecedented at least on land. > In 1945, the Makran earthquake in Pakistan triggered the sudden emergence > of three offshore mud volcanoes, and in March 1999 a mud volcano rose out > of the water overnight to form Malan Island, 3 kilometres from Pakistan's > coast. It is hard to estimate the volume of mud created by such underwater > eruptions. And, notes Rice: "Because the extrusion of mud and toxic gas > occurs on the seabed it does not threaten human life and does not make the > headlines." > 'Well-kick' the sudden surface eruption of gas and mud during offshore oil > drilling is common, but usually stops after a few days. Delisle recalls a > smaller-scale incident in the 1960s where a geothermal well in the > Wairakei geothermal field, New Zealand, ran wild: it took 3 months to stop > the geothermal steam that found its way to the surface alongside the > original borehole. > > Can the disaster be stopped? > > Nobody knows. So far, nothing has worked. PT Lapindo Brantas's senior > vice-president Imam Agustino has been quoted saying: "The best-case > scenario [for stopping the mudflow] is now mid-November, but I have to > admit it might never be stopped." > Visit our newsblog to read and post comments about this story. > Article Copyright © 2006 MacMillan Publishers Ltd. > <http://www.macmillan.com> All rights reserved. This material may not be > published, broadcast, rewritten, or redistributed. > > --------------------------------------------------------------------- ----- PIT IAGI ke 35 di Pekanbaru ----- Call For Papers until 26 May 2006 ----- Submit to: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, send email to: iagi-net-unsubscribe[at]iagi.or.id To subscribe, send email to: iagi-net-subscribe[at]iagi.or.id Visit IAGI Website: http://iagi.or.id Pembayaran iuran anggota ditujukan ke: Bank Mandiri Cab. Wisma Alia Jakarta No. Rek: 123 0085005314 Atas nama: Ikatan Ahli Geologi Indonesia (IAGI) Bank BCA KCP. Manara Mulia No. Rekening: 255-1088580 A/n: Shinta Damayanti IAGI-net Archive 1: http://www.mail-archive.com/iagi-net%40iagi.or.id/ IAGI-net Archive 2: http://groups.yahoo.com/group/iagi ---------------------------------------------------------------------
