Coseismic Ground Rupture of the 15 October 2013 Magnitude (<i>M</i>_<i>W</i>) 7.2 Bohol Earthquake, Bohol Island, Central Philippines

Abstract

Abstract The 15 October 2013 magnitude ( M W ) 7.2 Bohol earthquake produced an ~50‐km‐long, ~12‐km‐wide northeast trending zone of uplift with an ~8‐km‐long discontinuous ground rupture indicating predominantly reverse‐slip movement on a southeast dipping fault. Documentation of the nearly continuous northern terminus of the 2013 Bohol earthquake ground rupture revealed its association to preexisting scarps of the previously unmapped, Quaternary‐active North Bohol Fault. Trenching across the rupture at four sites not only reveals the geometry and kinematics of the fault but also shows at least one or two pre‐2013 surface rupturing events. Onshore geologic mapping and offshore seismic reflection profiles demonstrate the presence of an island‐wide, northeast‐southwest trending fold‐and‐thrust belt through which deformation related to the regional shortening across the Visayan Sea Basin in the central Philippines is likely distributed.