Source process of the Ms = 6.6, Udayapur earthquake of Nepal–India border and its tectonic implication

The 1988 Udayapur Earthquake of Nepal–India border occurred at longitude 86.6°E and latitude 26.7°N in the vicinity of the rupture area of the great earthquake of 1934. We estimated the focal parameters and slip model of this earthquake by waveform modeling of the teleseismic P-waves using a multiple event deconvolution method. We analyzed 10 waveform data retrieved from IRIS, GDSN and GEOSCOPE. We found this earthquake to be a double-event earthquake with a time lag of about 8 s between the two successive subevents. Focal mechanism solution obtained in this study is consistent with already published solutions. Depth constraints obtained in this study indicates this earthquake to rupture the lower crust of the subducting Indian slab. The slip model with a fault dimension of 39 km × 21 km estimated in this study reveals one main rupture area (asperity) at the main hypocentral region with a maximum slip of 3.38 m.