סמינר בחוג למדעי כדור הארץ: Passive Seismic Study of a Magma-Dominated Rift: the Salton Trough
Shahar Barak, Stanford University
Akiva Bar-Nun, TAU
There are only two places in the world where a mid-ocean ridge system changes into a transform system and runs into the continent: The Salton Trough, southern California, and the Gulf of Elat. The Salton Trough is a large transtensional basin, which lies in the transition zone between the Gulf of California oblique-rift system and the right-lateral San Andreas Fault. Although extensively studied in the past, using both passive- and active- source methods, the lower crust and upper mantle under the Salton Trough remain poorly imaged, and still, very little is known about the total volume of intrusion into the crust, or the magma distribution within and beyond the rift margins. In early 2011, I deployed a 2-year campaign array of densely-spaced broadband seismometers across the Salton Trough. In this talk, I will present results from a high-resolution 3D velocity model of southern California, that I created using cross-correlations of ambient noise. I will show new information about the extent and mode of magmatism under the Salton Trough. I will also show tomographic images across the San Andreas Fault, which may have very important repercussions for understanding the tectonics of the region and for seismic hazard.
מארגנת הסמינר: ד"ר רוית חלד