The source process of the 2010 Mentawai
Tsunami is estimated by using tsunami waveforms at a DART station and tide
gauge stations around the Indian Ocean. The inversion results show that the
major slip region for the October 25 2010 Mentawai earthquake is located near
epicenter. The slip amount near the epicenter is about 1.3 to 2.5 m, and the
slip amount around the trench is about 1.8 m. The seismic moment calculated
from the slip distribution is 1.07 x 10^{21}
Nm (moment magnitude Mw= 8.0), larger than that obtained from seismic
inversion. However, comparison of the measured tsunami heights at Mentawai
islands region with the calculated maximum coastal tsunami heights from slip
distribution shows that the simulated tsunami heights is underestimated the
measured tsunami heights at Mentawai islands region.

The distribution of aftershocks and the area of dominant slip in the slip distribution model from tsunami inversion suggest that the event ruptured up-dip from the point of nucleation (hypocenter) and very near the trench. Such near-trench rupture supports that this earthquake was a "tsunami earthquake".

The fringes calculated from InSAR data show one cycle of color corresponding to 2 pi radians phase change. The one color cycle of 2 pi radians phase change would correspond to 2.8 cm of displacement along the radar line of sight (LOS) for South Pagai island of Mentawai islands region. The amount of displacement in the direction of the line of sight calculated from tsunami inversion is also estimated to be one color cycle of 2 pi radians phase change.