NUMERICAL SIMULATION OF THE 1992 FLORES TSUNAMI IN INDONESIA: DISCUSSION ON LARGE RUNUP HEIGHTS IN THE NORTHEASTERN FLORES ISLAND

Fumihiko Imamura, Tomoyuki Takahashi, Nobuo Shuto

Abstract


Tsunami source model is disscused by numerical analysis for the 1992 Flores Island, Indonesia. Computed results with the composite fault model with two different slip values show good agreements with the measured run-up heights in the northeastern part of Flores Island, except for those in the southern shore of Hading Bay and at Riangkroko. The landslides in the southern part of Hading Bay could generate local tsunamis of more than 10 m, which could be the reason of discrepancy between the measured and computed one. The circular-arc slip model proposed in this study for wave generations due to landslides shows better results than the subsidence model. It is, however, difficult to reproduce the tsunami run-up height of 26.2 m at Riangkroko, which was extraordinarily high compared to other places. Two villages located on the southern coast of Babi Island, back side of the tsunami source region, received severe damages. The simulation model shows that the reflected wave along the northeastern shore of Flores Island, accompanying a high hydraulic pressure, could be the main cause of huge damages in the southern coast of Babi Island.

Keywords


Flores Island; numerical simulation; tsunami; run up; Indonesia

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