ESTIMATES OF WAVE HEIGHTS ON THE COAST OF CHILE FROM A TSUNAMI GENERATED BY AN EARTHQUAKE July 8, 1730

Abstract

The historical earthquake and tsunami occurred almost 300 years ago on July 8, 1730 in the region of Valparaiso, Chile is studied. The earthquake and tsunami of 1730 were considered to be the largest occurred in Chile since the beginning of recorded history. The earthquake destroyed buildings along more than 1000 km coastline and generated a large tsunami. Estimates of the magnitude of the earth- quake lie in the range of M ~ 9–9.3. The data given in historical documents on the tsunami, caused by this catastrophic earthquake, supports and documents the strong destruction on the Chilean coast, es- pecially in the coastal cities of Concepcion and Valparaiso, where waves, according to historical re- cords on the coasts, reached 9m and 11m, respectively. The parameters of the earthquake source are poorly understood, but, according to estimates from various sources, the earthquake source was about 600-1000 km long along the Chilean coast. In the work, more than 15 scenarios for numerical simula- tion of the generation and propagation of tsunami waves up to a 5-meter isobath is carried out, de- pending on the magnitude of the earthquake and, accordingly, on the size of the earthquake source. The numerical simulation was performed within the keyboard model of the earthquake source; the number of blocks in the computations corresponds to the number of faults in the earthquake source and varied from 2 to 12.

Keywords

• tsunamigenic catastrophic earthquakes
• tsunami waves
• numerical simulation
• chilean coast