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Geophysics seminar: Sunyoung Park (Caltech) "Probing Earth’s Near-Surface Structure Using Body-Wave Polarization"

04/02/2019 - 12:00pm
Munk Conference Room
Event Description: 

Talk Abstract:

Near-surface seismic structure is crucial in assessing earthquake hazards, since it is directly
related to the level of ground shaking. Constraining the near-surface structure, however, is
challenging, especially in the environments where drilling or field experiments using vibro-
trucks or explosives are not practical options. In this talk, I will introduce a new non-invasive
technique to obtain near-surface seismic wave speeds based on the fact that the wave speed
immediately beneath a seismometer controls the recorded orientations of arriving seismic
waves. The technique is applied to High-Sensitivity Seismograph Network in Japan to generate
a map of near-surface compressional and shear wave speeds. The lateral variations in wave
speeds correlate with geological and physical features such as topography and volcanoes. This
technique requires minimal computation resources, and opens a new path to study the
shallowest (~100 m) crustal structures non-invasively and inexpensively. It can also be
expanded in the depth dimension by examining the frequency dependence and in the time
dimension by analyzing earthquakes from different time periods.

For more information on this event, contact: 
Johnny Zhang
Event Calendar: