NEES@UCSB

The Wildlife facility was recently enhanced to include a unique cross-hole array experiment. The new permanent cross-hole array includes three geophones and a solenoid-activated dual-direction hammer source at 4.6 meters depth. And an additional geophones at 2.5m depth deployed directly above the 4.6m geophones in the casing furthest from the source. The system is set to trigger once per week automatically with both upward and downward hammer strikes, thus providing the capability to measure shear-wave velocity on a weekly basis. The system is also programmed to automatically activate the hammer source at shorter time intervals immediately following a large earthquake.

Using ground motions recorded from a M4.1 event at the NEES@UCSB Garner Valley field site, Amit Chourasia of the San Diego Supercomputer Center generated animations of the ground motion response in the soil column. These are the first animations produced showing site amplifica- tion that use real earthquake data recorded in the soil column. Videos and interactive animations allow users to investigate the amplification of ac- celerations, velocities, and displacements in soil layers of various stiffnesses down to a depth of 150 meters.