Seismic Observations Following the July 2017 Pasco County, West Florida, Sinkhole Collapse

Authors

Jochen Braunmiller, University of South FloridaFollow
Glenn Thompson, University of South FloridaFollow
Stephen R. McNutt, University of South FloridaFollow
Kathryn Dorn, University of South FloridaFollow
David B. Graybeal, University of South FloridaFollow
Alexandra Farrell, University of South FloridaFollow
Lori D. Collins, University of South FloridaFollow
Travis Doering, University of South FloridaFollow
David Eilers, University of South FloridaFollow
J. Gonzales, University of South Florida
Henok G. Kiflu, University of South FloridaFollow
Sarah Kruse, University of South FloridaFollow
Shawn M. Landry, University of South FloridaFollow
Tonian Robinson, University of South FloridaFollow
Garrett T. Speed, University of South FloridaFollow

Document Type

Presentation

Publication Date

5-15-2018

Abstract

A sinkhole collapse on 14 July 2017 destroyed two homes and required evacuation of 9 additional residences in Land O’Lakes, Florida. The sinkhole formed rapidly and within 10 hours reached most of its final size of approximately 40 by 50 m and a maximum depth of about 15 m. According to Pasco County officials, this is the largest sinkhole to have formed in the county during the last 30 years. The site is located near two natural lakes and occurs within an area of well-developed karst. The county allowed USF geoscientists to study the sinkhole resulting in an extensive collection of LiDAR, GPR, and lake-bottom profiling data. The seismology group installed one broadband 3-component seismometer on 25 July ~20 m W of the sinkhole edge and a second one on 27 September about 10 m E of the sinkhole edge. Data are recorded continuously at 200 Hz. Drilling to understand soil structure integrity and remediation work to stabilize the sinkhole led to extreme noise levels during daytime operations through most of August 2017. Nighttime noise is lower, but due to nearby houses, sensors pick up strong 60 Hz noise caused by AC units. The only signal unequivocally attributable to the sinkhole occurred on 5 August just after stabilization work, consisting of partial backfilling with limestone rocks, began that caused the sinkhole to widen by about 3 m along its entire western edge. After completion of stabilization work, no further signals have been detected from the sinkhole. Besides sinkhole monitoring, we recorded several large global earthquakes, e.g., the Mw=8.2 and Mw=7.1 Mexico earthquakes on September 8 and 17, respectively, as well as Hurricane Irma as it passed within 20 miles as a quickly weakening category 1 hurricane. In addition to outreach and sinkhole documentation as part of a multi-sensor approach, we use the site to train seismology graduate students in field practices and conducted a class field trip.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Presented at the Seismological Society of America Annual Meeting on May 15, 2018 in Miami, FL

Scholar Commons Citation

Braunmiller, Jochen; Thompson, Glenn; McNutt, Stephen R.; Dorn, Kathryn; Graybeal, David B.; Farrell, Alexandra; Collins, Lori D.; Doering, Travis; Eilers, David; Gonzales, J.; Kiflu, Henok G.; Kruse, Sarah; Landry, Shawn M.; Robinson, Tonian; and Speed, Garrett T., "Seismic Observations Following the July 2017 Pasco County, West Florida, Sinkhole Collapse" (2018). School of Geosciences Faculty and Staff Publications. 2192.
https://digitalcommons.usf.edu/geo_facpub/2192