Indonesian region
This is one of the most seismically active regions on the planet. Events will be added to this page as they occur MAJOR RECENT INDONESIAN EARTHQUAKES
Map of recent important Indonesian earthquakesfrom left to right: Dec 2004, Mag 9.0: Mar 2005, Mag 8.7: Sep 2009, Mag 7.5 July 2006, Mag 7.7 : May 2006, Mag 6.3, Oct 2009, Mag 6.9 Indonesian earthquakes in 2004 & 2005 ( Mag 7+) Aftershocks of Dec 2004 event (region 1 - 7 Deg North, 93 - 99 Deg east - source ANSS catalogue) 26 Dec 2004 - 26 Jan 2005
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TECTONICS OF THE INDONESIAN REGIONThe plate tectonics of this region, particularly at the eastern end, in the region of the Banda Sea, is perhaps the most complicated of any region in the world. The sharp curve in the Banda Arc is attributed to two distinct dipping slabs. Firstly, we have the Australian plate being subducted under the Asian Plate, and dipping to the north. The strike of this subduction zone is swung around to the north to the east of Timor. To the north of this we have the Pacific Plate, which is being carried to the west by the Tarera-Aiduna Fault, and then being subducted to the south west at the Seram Trough. This interpretation has been clarified by the work of Das ( Journal of Geophysical Reseach, 2004), who has accurately relocated more than 800 earthquakes in the area. Below - ISC locations from 1964 - 1996 Mag > 4.5 and deeper than 50 km, figure from Das (2004) for more on tectonics of the Indonesian region, follow this link |
GREAT EARTHQUAKE - INDONESIA - 26 Dec 2004This earthquake was the largest in the world since a Magnitude 9.2 event in Alaksa in 1964. It was the 4th largest event in the world since 1900. It is estimated to have caused rupturing along the plate boundary, in a roughly north-north-west direction, of at least 500 km. The average displacement has been estimated at 15 metres. The zone of aftershocks is at least 1300 km long. As we all know, it caused a tsunami of devastating dimension, having caused deaths as far away as the east coast of Africa. Minor tsunami effects were recorded on the west coast of Australia, and they are documented elsewhere on this web site. The current estimate of magnitude is 9.0 ( surface wave magnitude or MS), although some sources have computed a larger magnitude, and it has been suggested that this earthquake was the largest instrumentally recorded earthquake in the world, ever! The earthquake did not have any foreshocks large enough to be located by international agencies - that is, larger than about magnitude 4. However, there have been thousands of aftershocks. Up to Jan 14, 2005, there have been 18 aftershocks of magnitude 6 or greater. Five of these were on the same day as the earthquake, four on the following day, and three two days after that. The most recent was on January 9 (as at 14 Jan 2005). The largest aftershock was a magnitude 7.5 event approximately 3 hours after the main shock. Follow link for descriptions of the effects of the tsunami in Western Australia Below - map of all earthquakes in the region, 15 Dec to 14 Jan ( source IRIS) Below - map for same period, showing event of Mag 6.0 and greater ( source - IRIS) Below - magnitude 7 & greater earthquakes in the region since 1960 Link to USGS site on this earthquake below maps by the USGS Other Large events this century 1952 - Kamchatka - Mag 9.0 1957 - Andreanof Is, Alaska - Mag 9.1 1960 - Chile - Mag 9.5 1964 - Pr. William Sound Alaska - Mag 9.2 each of these events caused destructive tsunamis |
BANDA SEA, 02 MARCH 2005, MAG 7.1 "Earthquake shakes Darwin" A strong earthquake has rocked parts of Darwin, with tremors lasting several minutes and felt right across the city and in rural areas. Geoscience Australia says the earthquake measured 7.2 on the Richter scale with its epicentre about 500 kilometres east north-east of East Timor in the Banda Sea. The director of the Australia Seismological Centre in Canberra, Kevin McCue, says the earthquake is unlikely to have caused any damage because it occurred at a great depth. "The tsunami risk is zero for an earthquake of that focal depth," he said. "It's not big enough at that focal depth to have ruptured the sea floor, so there's zero chance of a tsunami." Residents reported the earthquake hitting the capital of the Northern Territory at around 8:20pm ACST. "We felt the house shaking, we're in a high house and the house was shaking," resident Sandy White said. "I have a china cabinet, the glass and all the china and the crystal in the cabinet was shaking. I had a glass of water and it was nearly slopping over. "It was quite spectacular, I've been in a lot of earthquakes and this one was fairly strong I would say." Peter Kilgor from Palmerston says he was sitting in his lounge room when the quake hit. "[There were] half a dozen or a dozen shakes, I mean it was moving and pot lids were falling off the pots on the stove because we just finished cooking tea and [had] the dishes sitting there and the pot heads are sliding around." Another Darwin resident, Carolyn Reynolds, was driving her car at the time. "I felt that my car had a flat tyre and the car was beginning to wobble, and there was a really weird noise that sounded like a flat tyre and then I thought maybe it was an aeroplane," she said. "I wound down the windows and the noise continued. I stopped the car, realised it was the earth moving and carried on to home and when I got home the whole house was shaking and the bannisters which are made of metal were vibrating and it was just incredible." Diners in Darwin's main social area of Mitchell Street say they felt the tremor for several minutes, with one staff member at a nightclub saying plates shook and punters went onto the street. Hundreds of people who were attending a football dinner at the casino evacuated, fearing they were about to face a serious earthquake. One diner said that given the recent devastating Asian tsunami, she feared the worst. The football dinner resumed as normal and punters on Mitchell Street also resumed their social activities. The earthquake was also felt in the capital of East Timor, with a caller to ABC Radio Gino saying there was a slight shake at a Dili hotel he was in. |
Earthquakes in Irian jaya Jan 1990-Jan 1994 depth < 100 km ( map from IRIS website) Bathymetry of Irian Jaya region ( map from National Geophysical Data Center) |