The 1992 Nicaragua earthquake: A slow tsunami earthquake associated with subducted sediments

摘要: The 1992 Nicaragua earthquake was a ‘tsunami earthquake‘; that is, it generated tsunamis disproportionately large for its surface-wave magnitude, M_s. moment M_w, determined from long-period (~250-s) surface waves, 7.6, significantly larger than the 20-s M_s of 7; this M_s–M_w disparity is also characteristic tsunami earthquakes. first to be captured by modern broadband seismic networks, allowing us present here seismograms sufficiently high quality make inferences about rupture mechanisms. We conclude slow thrust which occurred on subduction interface between Cocos and North American plates, because absence sediments trench floor offshore Nicaragua, slip propagated up-dip all way ocean bottom, exciting tsunamis. occurrence plate filled with soft subducted caused process slower in ordinary subduction-zone Our results reinforce idea warning systems using (≥100-s) waves are necessary reduce hazard type earthquake.