A deep outer‐rise reverse‐fault earthquake immediately triggered a shallow normal‐fault earthquake: The 7 December 2012 off‐Sanriku earthquake (MW 7.3). Issue 16 (22nd August 2013)

• Record Type: Journal Article
• Authors: Harada, Tomoya; Murotani, Satoko; Satake, Kenji
• Is Part Of: Geophysical research letters. Volume 40:Issue 16(2013:Aug.)
• Page Start: 4214
• Page End: 4219
• Publication Date: 2013-08-22
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/grl.50808
• Languages: English
• ISSNs: 0094-8276

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>[1] Teleseismic body wave analysis revealed that the 7 December 2012 off‐Sanriku earthquake (<italic>M_W</italic> 7.3) at the outer rise of Japan Trench consisted of two successive subevents. The first subevent with reverse‐fault mechanism (Event 1, <italic>M_W</italic> 7.1) at 56 km depth was followed by, approximately 20 s later, the second subevent with normal‐fault mechanism (Event 2, <italic>M_W</italic> 7.2) at 6 km depth. Finite‐fault slip models show that the slip of Event 1 was concentrated around the initial rupture point with the maximum of 2.7 m and that Event 2 had two asperities with the maximum of 4.5 m at both sides of the initial rupture point. The static Coulomb Failure Function analyses suggested that Event 1 triggered Event 2 and that both subevents were promoted by the 2011 Tohoku earthquake (<italic>M_W</italic> 9.1).</p> </abstract>