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Abstract. Two major earthquakes near the Central Kuril Islands (M w =8.3 on 15 November 2006 and M w =8.1 on 13 January 2007) generated trans-oceanic tsunamis recorded over the entire Pacific Ocean. The strongest oscillations, exceeding several meters, occurred near the source region of the Kuril Islands. Tide gauge records for both tsunamis have been thoroughly examined and numerical models of the events have been constructed. The models of the 2006 and 2007 events include two important advancements in the simulation of seismically generated tsunamis: (a) the use of the finite failure source models by Ji (2006Ji ( , 2007 which provide more detailed information than conventional models on spatial displacements in the source areas and which avoid uncertainties in source extent; and (b) the use of the three-dimensional Laplace equation to reconstruct the initial tsunami sea surface elevation (avoiding the usual shallowwater approximation). The close agreement of our simulated results with the observed tsunami waveforms at the openocean DART stations support the validity of this approach. Observational and model findings reveal that energy fluxes of the tsunami waves from the source areas were mainly directed southeastward toward the Hawaiian Islands, with relatively little energy propagation into the Sea of Okhotsk. A marked feature of both tsunamis was their high-frequency content, with typical wave periods ranging from 2-3 to 15-20 min. Despite certain similarities, the two tsunamis were essentially different and had opposite polarity: the leading wave of the November 2006 trans-oceanic tsunami was positive, while that for the January 2007 trans-oceanic tsunami was negative. Numerical modeling of both tsunamis indicates that, due to differences in their seismic source properties, the 2006 tsunami was more wide-spread but less focused than the 2007 tsunami.

Wave arrival times obtained from coastal tide gage and satellite altimetry records for the Indian Ocean are used to delineate the source region for the December 26, 2004 Sumatra tsunami. Findings define a curved, 250‐km wide, 1000‐km long tsunami source region centered over the Sunda Subduction Zone, which closely matches the seismic source estimated from broadband geophysical data. Imbedded in this general region are “hot spots” associated with the southern fast‐slip and northern slow‐slip domains which served as distinct source areas for the destructive waves that inundated the coast of the Indian Ocean.