Source of the July 2006 West Java tsunami estimated from tide gauge records

The source of the West Java tsunami of July 17, 2006, which was generated during a large earthquake near the Sunda trench, is constrained by tsunami waveforms that were recorded on six tide gauges around the Indian Ocean. The tsunami travel times poorly constrain the source area, probably because shallow bathymetry near these gauges is not well known. Inversion of tsunami waveforms, however, reveals that the tsunami source was about 200 km long. The largest slip, about 2.5 m for instantaneous rupture model, was located about 150 km east of the epicenter. Most of the slip occurred on shallow parts of the fault, indicating that this earthquake shares the same characteristics with “tsunami earthquakes” which generate abnormally large tsunamis compared with ground shaking. The slip distribution yields a total seismic moment of 7.0 × 1020 Nm (Mw = 7.8).