At periods greater than 1000 seconds, Earth’s seismic free oscillations have anomalouslylarge amplitude when referenced to the Harvard Centroid Moment Tensor faultmechanism, which is estimated from 300- to 500-second surface waves. By using morerealistic rupture models on a steeper fault derived fromseismic body and surface waves,we approximated free oscillation amplitudes with a seismic moment (6.5 x 1022NewtonImeters) that corresponds to a moment magnitude of 9.15. With a ruptureduration of 600 seconds, the fault-rupture models represent seismic observationsadequately but underpredict geodetic displacements that argue for slow fault motionbeneath the Nicobar and Andaman islands
Earth’s free oscillations excited by the 26 December 2004 Sumatra-Andaman earthquake / Park, J.; Song, T. A.; Tromp, J.; Okal, E.; Stein, S.; Roult, G.; Clevede, E.; Laske, G.; Kanamori, H.; Davis, P.; Berger, J.; Braitenberg, Carla; Van, Camp; Lei, X.; Sun, H.; Xu, H.; Rosat, S.. - In: SCIENCE. - ISSN 0036-8075. - STAMPA. - 308:(2005), pp. 1139-1144. [10.1126/science.1112305]
Earth’s free oscillations excited by the 26 December 2004 Sumatra-Andaman earthquake
BRAITENBERG, CARLA;
2005-01-01
Abstract
At periods greater than 1000 seconds, Earth’s seismic free oscillations have anomalouslylarge amplitude when referenced to the Harvard Centroid Moment Tensor faultmechanism, which is estimated from 300- to 500-second surface waves. By using morerealistic rupture models on a steeper fault derived fromseismic body and surface waves,we approximated free oscillation amplitudes with a seismic moment (6.5 x 1022NewtonImeters) that corresponds to a moment magnitude of 9.15. With a ruptureduration of 600 seconds, the fault-rupture models represent seismic observationsadequately but underpredict geodetic displacements that argue for slow fault motionbeneath the Nicobar and Andaman islandsPubblicazioni consigliate
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