Graduation Year
2023
Document Type
Thesis
Degree
M.S.
Degree Name
Master of Science (M.S.)
Degree Granting Department
Geosciences
Major Professor
Stephen McNutt, Ph.D.
Committee Member
Jochen Braunmiller, Ph.D.
Committee Member
Rocco Malservisi, Ph.D.
Abstract
The fact that Florida is an earthquake-free region has caused seismologists to pay less attention to it. Few earthquakes in this state mean it is not a usual practice to study the propagation of seismic waves. However, utilizing data from quarry blasts, we studied wave propagation in this region. The primary objective of the project is to investigate the near-surface P-wave velocity structure and factors that may affect it. We also analyzed the amplitude of signals versus distance and blast size. A network of up to 10 Raspberry Shake instruments around the NW Miami-Lakes mining area was deployed where four main quarry mines are recognized. More than 1600 blast waveforms were recorded from July 2019 to December 2022, and a catalog was created for measuring parameters. Later, we received detailed information about 447 blasts from the Miami-Dade Pilot Program of the Florida State Fire Marshal office and chose a subset of 165 high-quality events. We located these events in SEISAN and applied a grid search to reduce the misfit for the events' locations. Average P-wave velocity measured from travel time versus distance plots ranges from 4.6 to 5.4 km/s. In addition, first and second polynomials were fit to the data, and the average and root mean square errors were used to evaluate the goodness of fit. The result showed smaller error differences for the quadratic fit that suggests velocity changes with depth. Furthermore, peak-to-peak amplitudes of four distinct waves are compared with the changes in distance and explosive amounts of blasts. A decrease in amplitude versus distance with a combination of 1/r and 1/√r is observed.
Scholar Commons Citation
Moslemi, Elham, "Determining the P-wave Velocity Structure in the Near-Surface of NW Miami, Florida, Using Quarry Blasts" (2023). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/10070