Comparison of Teleseismic Responses at a Co-Located High-Rate and High-Density Tilt and Seismic Array in Florida

Session: Advances in Upper Crustal Geophysical Characterization [Poster]
Type: Poster
Date: 4/29/2020
Time: 08:00 AM
Room: Ballroom
Description: 

Karst aquifers are important freshwater storage regions and complex hydrogeological systems. To assess our ability to characterize these systems non-intrusively, we have deployed a network of seismometers (12 short period, 2 broadband), tiltmeters (4 shallow borehole, 2 platform instruments) and hydrological sensors at O’Leno State Park, Florida. Here, the Santa Fe River enters a subsurface conduit system at River Sink and reemerges about 6 km downstream at the River Rise, with some surface interaction at a few Karst windows. The primary interest of our deployment is the measurement of ground responses to hydrological recharge pulses. The resulting network geometry has all but one tiltmeter co-located with a short period seismometer at distances generally less than 5 meters. The geophysical instruments sample at very high rates with seismometers collecting 500 samples per second and the tiltmeters collecting 1 sample per second. In addition to the intended observations of local ground deformation due to hydrological processes, the high-rate tiltmeters have recorded exceptional records of teleseismic earthquakes.

Here, we present a comparison of tilt and seismic responses to large magnitude earthquakes such as the 2018 M 7.1 Anchorage earthquake, the 2019 Ridgecrest sequence, a 2019 M 6.3 earthquake in Mexico and other large magnitude events. Our preliminary analyses show that the tiltmeters are sensitive to global M 6+ events. They clearly record P, S and surface waves in phase with the co-located seismometers. We explore array processing techniques with the tilt sensors.

Presenting Author: Ronni Grapenthin

Authors