The 17 July 2006 Java tsunami earthquake

Abstract

The 17 July 2006 Java earthquake involved thrust faulting in the Java trench and excited a deadly tsunami (∼5–8 m) that inundated the southern coast of Java. The earthquake's size estimates vary significantly with seismic wave period: very long-period signals (300–500+ s) indicate a seismic moment of 6.7 × 10^(20) Nm (M_w = 7.8), M_S (∼20 s) = 7.2, m_b (∼1 s) = 6.2, while shaking intensities (3–10 Hz) were ≤ MMIV. The large tsunami relative to MS characterizes this event as a tsunami earthquake. Like previous tsunami earthquakes, the Java event had an unusually low rupture speed of 1.0–1.5 km/s, and occurred near the up-dip edge of the subduction zone thrust fault. Most large aftershocks involved normal faulting. The rupture propagated ∼200 km along the trench, with several pulses of shorter period seismic radiation superimposed on a smooth background rupture with an overall duration of ∼185 s.