An International Tsunami Survey Team ITST conducted field surveys of tsunami effects on the west coast of northern and central Sumatra and offshore islands 3–4 months after the 26 December 2004 tsunami. The study sites spanned 800 km of coastline from Breuh Island north of Banda Aceh to the Batu Islands, and included 22 sites in Aceh province in Sumatra and on Simeulue Island, Nias Island, the Banyak Islands, and the Batu Islands. Tsunami runup, elevation, flow depth, inundation distance, sedimentary characteristics of deposits, near-shore bathymetry, and vertical land movement subsidence and uplift were studied. The maximum tsunami elevations were greater than 16 m, and the maximum tsunami flow depths were greater than 13 m at all sites studied along 135 km of coastline in northwestern Sumatra. Tsunami flow depths were as much as 10 m at 1,500 m inland. Extensive tsunami deposits, primarily composed of sand and typically 5–20 cm thick, were observed in northwestern Sumatra. DOI: 10.1193/1.220772

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S U M M A R YThe M w = 8.4 earthquake on 2007 September 12, offshore of the Bengkulu province of Sumatra, Indonesia, generated a moderate tsunami with run-up heights of up to 4 m as measured by Indonesian and international researchers in the days following the earthquake. The tsunami was observed along 250 km of coastline and caused damage at several locations. The largest wave heights and most severe inundation were observed about 50 km to the northwest of Bengkulu; elsewhere the effects were less severe-with the exception of substantial inundation at a site 150 km to the south. In addition to presenting the field data, we conduct a modelling study and compare the run-up heights and water-level predictions from four different seismic deformation models used to initialize a tsunami propagation and inundation model. Our comparative results suggest that, for this event, the estimates of fault parameters available immediately after determination of the earthquake size and location predicted the near-field run-up heights and distribution and far-field wave equally well as estimates obtained using more detailed descriptions of the seafloor deformation, as typically available hours or days after an event. We conclude that while detailed slip patterns can be important to the near-field run-up distribution, simple fault models can be used to rapidly assess the likely near-and far-field tsunami effects of a particular earthquake.

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On February 17,1996, at 0559 UT, a major earthquake with moment magnitude (Mw) 7.9 killed 107 people and caused major damage at Biak Island, 30–40 km southwest of the earthquake's epicenter (Figures 1 and 2). A devastating tsunami washed away all of the houses at Korim, a small village located in a narrow bay facing directly towards the incoming wave, and it left behind clear evidence of sand erosion and deposition that indicated how far the tsunami advanced. An unexpectedly large tsunami run‐up of 7.7 m was measured at Wardo in western Biak, which faces away from the primary tsunami source. This high run‐up may have been caused by a local submarine landslide.

On the evening of March 28, 2005 at 11:09 p.m. local time (16:09 UTC), a large earthquake occurred offshore of West Sumatra, Indonesia. With a moment magnitude (M w ) of 8.6, the event caused substantial shaking damage and land level changes between Simeulue Island in the north and the Batu Islands in the south. The earthquake also generated a tsunami, which was observed throughout the source region as well as on distant tide gauges. While the tsunami was not as extreme as the tsunami of December 26th, 2004, it did cause significant flooding and damage at some locations. The spatial and temporal proximity of the two events led to a unique set of observational data from the earthquake and tsunami as well as insights relevant to tsunami hazard planning and education efforts.

The potential of earthquake-tsunami in South Java is lower than those in

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