固体地球物理学术报告通知-20171024 Prof. Clifford Thurber
We deployed dense seismic arrays to image the shallow structure in the injection area of the Brady Hot Springs geothermal site in Nevada. The arrays were composed of 238 5 Hz, three-component nodal instruments and 8,700 m of distributed acoustic sensing (DAS) fiber-optic cable buried in surface trenches plus 400 m installed in a borehole. The geophone array had about 60 m instrument spacing in the target zone, whereas DAS channel separations were about 1 m, with a 10 m averaging (gauge) length. A large vibroseis truck (T-Rex) was operated at 191 locations.
Models with 100 m and 50 m horizontal node spacing were obtained, with vertical node spacing of 10 to 50 m. I will present our 3D Vp model from the vibroseis nodal and DAS data and a preliminary analysis of shear-wave structure from ambient noise data. I will also present a brief comparison of nodal and DAS data.