Long Period Seismic Moment Of The 2004 Sumatra Earthquake And

Long Period Seismic Moment Of The 2004 Sumatra Earthquake And The size of the earthquake is given by its moment magnitude mw, defined as mw = (log mo 1.5) – 10.73 from the seismic moment mo in dyn cm. thus the harvard cmt solution at periiods 300s and below measured a moment of 4e29 dyn cm giving mw 9.0, and the longest period normal mode 0s2 gives mo 1.0e30 dyne cm or mw 9.3. The two largest earthquakes of the past 40 years ruptured a 1600 kilometer long portion of the fault boundary between the indo australian and southeastern eurasian plates on 26 december 2004 [seismic moment magnitude (mw) = 9.1 to 9.3] and 28 march 2005 (mw = 8.6). the first event generated a tsunami that caused more than 283,000 deaths.

Long Period Seismic Moment Of The 2004 Sumatra Earthquake And The first reliable moment magnitude estimate1 of 9.0 was obtained several hours after the sumatra–andaman earthquake, but more recent, longer period, normal mode analyses have indicated that it. Analysis of the earth’s longest period normal modes shows that the december 2004 sumatra–andaman earthquake was much larger (m w 9.3) than initially inferred from surface wave data and involved slip on a much longer fault than initially inferred from body wave data. the seismic moment and relative excitation of the normal modes indicate that the entire aftershock zone ruptured, consistent. The 26 december 2004 sumatra andaman earthquake initiated slowly, with small slip and a slow rupture speed for the first 40 to 60 seconds. then the rupture expanded at a speed of about 2.5 kilometers per second toward the north northwest, extending 1200 to 1300 kilometers along the andaman trough. peak displacements reached ∼15 meters along a. The 2004 sumatra earthquake was one of the largest events to occur in a subduction zone in the past 50 years. seismic reflection data for this subduction zone reveal thrust faults cutting across.