The 17 July 2006 Tsunami Earthquake in West Java, Indonesia

Abstract

A tsunami earthquake ( Mw = 7.7) occurred south of Java on 17 July 2006. The event produced relatively low levels of high-frequency radiation, and local felt reports indicated only weak shaking in Java. There was no ground motion damage from the earthquake, but there was extensive damage and loss of life from the tsunami along 250 km of the southern coasts of West Java and Central Java. An inspection of the area a few days after the earthquake showed extensive damage to wooden and unreinforced masonry buildings that were located within several hundred meters of the coast. Since there was no tsunami warning system in place, efforts to escape the large waves depended on how people reacted to the earthquake shaking, which was only weakly felt in the coastal areas. This experience emphasizes the need for adequate tsunami warning systems for the Indian Ocean region. Following the disastrous tsunamis of 26 December 2004 and 28 March 2005 in Indonesia, yet another earthquake caused a tsunami with a large number of deaths and vast property damage. The 17 July 2006 West Java earthquake ( Mw = 7.7) was located offshore near the trench of the Sunda subduction zone south of Java. The thrust earthquake produced a large tsunami along the southern coast of Java that resulted in more than 600 deaths and more than 75,000 people displaced. This event was a “tsunami earthquake,” meaning that the levels of high-frequency seismic radiation were relatively low for the size of the event. The earthquake was only weakly felt in regions where large tsunami run-ups occurred, and this was one likely cause for the large number of casualties. Several other notable earthquakes in the Java region have resulted in damaging tsunamis over the years. The Mw = 7.8 earthquake of 2 June …