Southwest Pacific Seismic Experiment (SPaSE)

The SPaSE project was a two year deployment of 12 broadband PASSCAL instruments in Fiji, Tonga, and Niue Island. Earthquakes recorded by SPaSE stations are used to study the structure of the subducting slab using phases converted at the upper slab interface, dispersion of phases traveling up the slab, and comparison of travel times between phases traveling inside and outside of the slab. The structure of the back arc basin has been studied utilizing regional earthquakes and SKS splitting from teleseisms. This study has improved knowledge about the source processes of deep earthquakes in the most active deep seismic zone in the world, as well as provide better constraints on the tectonics of the deep slab, shallow trench and back-arc basin regions.

Map and Station Locations

IRIS Newsletter Article (project summary)

Initial Research Results

Photo Gallery

Principal Investigator

• Doug Wiens, Washington University

Links

• Lau Basin Ocean Bottom Seismograph Survey (LABATTS)
• Incorporated Reserach Institutions for Seismology (IRIS)
• PASSCAL Instrument Center
• Mineral Resources Department (Fiji)
• Ministry of Land, Survey, and Natural Resources (Tonga)
• International Institute of Seismology and Earthquake Engineering (IISEE)