Analysis of the Tsunami Generated by the Great 1977 Sumba Earthquake that Occurred in Indonesia

作者：Gusman Aditya R^*; Tanioka Yuichiro; Matsumoto Hiroyuki; Iwasaki Sin Iti

来源：Bulletin of the Seismological Society of America, 2009, 99(4): 2169-2179.

DOI：10.1785/0120080324

The great outer-rise earthquake (M(w) 8.3) occurred near the Sunda trench, Indonesia, on 19 August 1977. The earthquake has been previously studied using seismological data. The earthquake generated a large tsunami that caused severe damage in Sumbawa and Sumba Islands in Indonesia. The tsunami was also observed at tide gauges in Australia. We numerically computed a far-field tsunami, and we compared the observed tsunami waveforms on three tide gauges with the computed waveforms. We also numerically computed the tsunami inundation and compared the observed tsunami run-up of 8 m and tsunami inundation distance of 500 m in Lunyuk on Sumbawa Island with the computed ones. To explain the observed tsunami waveforms, tsunami run-up, and tsunami inundation distance, the slip amount is found to be 3 m on the assumed fault model (with a fault length of 200 km and fault width of 70 km). The rigidity is assumed to range between 6.0 and 6.8 x 10(10) N m(-2), and the range of the total seismic moment is calculated to be between 2.5 and 2.9 x 10(21) N m (M(w) 8.2), which is similar to those estimated by the previous seismological studies. Additionally, we calculated the ratio between the observed tsunami run-up and the computed maximum tsunami height along the coastline of Lunyuk. This ratio, called the amplification factor, may possibly be used to roughly estimate the tsunami run-up from a tsunami numerical calculation result on a coarse grid system.

• 出版日期2009-8-1
• 单位中国地震局地震研究所