Date of Award
Doctor of Philosophy in Oceanography
Marine Geology and Geophysics
The southwest Pacific is a tectonically complicated region consisting of two large igneous provinces (LIPs) on the ocean floor formed approximately 120 Ma. The formation of these two plateaus, the Ontong Java Plateau (OJP) and Manihiki Plateau (MP), along with one further south, is difficult to ascertain due to their remote location. Through the use of seismic modeling, we investigate these two features and the surrounding southwest Pacific to better understand their formation and deformation history.
3-dimensional vertical and tangential seismic wave speed models were computed for the two plateaus and surrounding upper mantle in the southwest Pacific. Pseudo 2D modelling of P/Pn phase arrivals across the OJP crust generated estimates of crustal thickness and mantle wave speed. We then attempted to model the effects of attenuation and wave speed beneath the OJP on QScS using 3-dimensional simulations of ScS phases. The seismic modelling provides new datasets for evaluating the LIPs and their formation and deformation history in the southwest Pacific.
Hirsch, Aaron C., "SEISMOLOGICAL INVESTIGATION OF THE ONTONG JAVA PLATEAU AND SURROUNDING PACIFIC UPPER MANTLE" (2021). Open Access Dissertations. Paper 1241.