Seismological instrumentation has traditionally been restricted to the 30% of the Earth’s surface that lies above sea level. Technological advances over the last several decades now allow retrieval of passive seismic data from the seafloor using ocean bottom seismographs (OBS). However, the ocean bottom environment presents additional challenges for seismic data collection and analysis, including limitations on recording duration, different noise characteristics, siting and instrument orientation issues, and timing uncertainties.
In this webinar, I will briefly describe OBS instrumentation and discuss how we attempt to mitigate some of the difficulties in collecting high quality passive seismic data in the oceans. I will describe the basic steps needed to design, propose and carry out an OBS deployment using the US National OBS Instrumentation Pool, now managed by IRIS with NSF funding. The application of traditional seismic analysis methods, such as surface and body wave tomography, noise correlation, receiver functions, and shear wave splitting to OBS data will be discussed. Finally I will close by showing results from ocean bottom seismograph experiments for several different environments, including mid-ocean ridges, transform faults, and subduction zones.
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