Document Type

Thesis

Date of Degree Completion

Summer 2020

Degree Name

Master of Science (MS)

Department

Geological Sciences

Committee Chair

Walter Szeliga

Second Committee Member

Breanyn MacInnes

Third Committee Member

Lisa Ely

Abstract

The Izu-Bonin Mariana (IBM) subduction zone is an over 3000-km long oceanic-oceanic convergence zone with no instrumental record of great subduction-zone earthquakes (Mw > 8.0). Due to the lack of great earthquakes and the oceanic-oceanic subduction style, previous researchers have speculated that the IBM does not produce great earthquakes. The same behavior was also proposed for the northern Japan and Cascadia subduction zones, which has since been proven false. We use the tsunami model GeoClaw (v5.6.0) with adjoint-guided refinement level flagging to simulate IBM earthquakes in three separate segments to produce estimates of wave heights at locations around the Pacific Basin that have the potential for written records dating back to the 1500s (such as western Pacific cities like Manila, Philippines and Hong Kong and eastern Pacific cities like Concepcion, Chile; Lima, Peru; and Acapulco, Mexico). The resulting simulated wave heights were assessed to determine whether a large IBM tsunami could have been noticed and written in historical records; possibly extending the aseismic behavior of the IBM further back in time. In addition, we look at the possibility of hiding great earthquakes in the Pacific Ocean. The best locations to search for tsunami records of a IBM earthquake event are the southern and eastern coasts of Japan and Hilo, Hawaii. The future studies using these results could lead to a reevaluation of the earthquake history within the IBM with the discovery of written tsunami records and paleo tsunami deposits.

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