July 17, 2006 Earthquake: Java, Indonesia

Reference #1053:

A major earthquake occurred 225 km (140 miles) NE of Christmas Island or 355 km (220 miles) S of Jakarta, Java, Indonesia at 3:19 PM local time Jul 17, 2006 in Indonesia. The earthquake occurred as a result of thrust-faulting on the boundary between the Australia plate and the Sunda plate. On this part of their mutual boundary, the Australia plate moves north-northeast with respect to the Sunda plate at about 59 mm/year. The Australia plate thrusts beneath the Sunda plate at the Java trench, south of Java, and is subducted to progressively greater depths beneath Java and north of Java. The earthquake occurred on the shallow part of the plate boundary, about 50 km north of the Java trench.

Reference #12010:

The July 17, 2006 Java earthquake was a classic tsunami earthquake with body-wave magnitude mb = 6.1, surface-wave magnitude Ms = 7.1, and moment magnitude Mw= 7.7 (Ekström et al., 2012; International Seismological Centre, 2013). Such a large variation in magnitude estimates is atypical and may indicate a deficiency in high-frequency radiation compared to low-frequency radiation (Ammon et al., 2006; Newman and Okal, 1998). The 2006 Java earthquake initiated at shallow depth (20 km, (International Seismological Centre, 2013); Fig. 1) and ruptured eastward along the trench axis for ∼200 km (Ammon et al., 2006; Bilek and Engdahl, 2007). Given the source dimension, the unusually long source duration (∼185 s) indicates anomalously slow rupture propagation for the event (Ammon et al., 2006; Bilek and Engdahl, 2007). The earthquake generated a large tsunami (∼8 m) resulting in over 800 fatalities (Fritz et al., 2007; Fujii and Satake, 2006; Mori et al., 2007). This was the second tsunami earthquake that struck the Java region since instrumental records began, and a Mw 7.8 earthquake in June 1994 produced an even larger tsunami (∼13 m), resulting in 250 fatalities (Abercrombie et al., 2001; Mori et al., 2007). These two earthquakes are only 600 km apart, highlighting the major tsunami hazard along the south coast of Indonesia (Mori et al., 2007).

Reference #12565:

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 runups occurred, and this was one likely cause for the large number of casualties.

Reference #13456:

The July 17, 2006, M 7.7 earthquake south of Java occurred as the result of shallow thrust faulting on or near the boundary between the Australia and Sunda plates, 50 km to the north of the Sunda-Java Trench that marks the sea-floor expression of this plate boundary. At the location of the earthquake, the Australia plate moves north-northwest relative to the Sunda plate, subducting at a velocity of about 59 mm/yr to progressively greater depths beneath Java and north of Java. The earthquake occurred on the shallow part of the plate boundary.

The region of the plate boundary between the Australia and Sunda plates is seismically highly active. From preliminary results, it appears that the July 17th earthquake is similar to the M 7.8 Java earthquake of June 2, 1994, which produced a tsunami that had a maximum run-up height of 13 m and resulted in more than 200 fatalities. That earthquake occurred south of Java about 600 km east-southeast of the July 17th earthquake, also as a result of thrust faulting on the shallow plate boundary.