The February 2024 M4.1 Earthquake Offshore Cape Canaveral, Florida
A rare seismic event occurred at 03:48 UTC on 8 February 2024, about 100 miles offshore east of Cape Canaveral, Florida. The ML 4.1 event was felt along the Florida Space Coast, raising the question of whether this was a tectonic earthquake. The USGS location at 28.55°N and 78.87°W places the event beneath the Blake Plateau, precluding a landslide. An explosive source could not be discarded initially as U.S. Navy “Full Ship Shock Trial” detonations equivalent to ML 3.9 were conducted as recently as August 2023 at a similar distance from the shore as the 8 February event, about 100 miles NNW of the 2024 epicenter. A comparison of seismic waveforms with the 2021 Navy explosions provides compelling evidence for a tectonic origin for the 2024 event. The explosions show strong, late arrivals due to water reverberations from shallow detonations. Late arrivals are absent in the 2024 records, suggesting a deeper crustal hypocenter. We relocated the event after adding the closest station, a Raspberry Shake instrument, placing the epicenter slightly farther north (28.6°-28.65°N) but event longitude remains ill-constrained due to the one-sided station distribution and the large station distances (D≥200 km). Regional moment tensor analysis in the 15-20 s band results in Mw 3.7, explaining low amplitudes relative to ML 4.1. Signal amplitudes constrain the magnitude, but the small number of good S/N waveforms hampers source mechanism resolution. Our preferred solution has a thrust mechanism at 11 km depth with large uncertainties. The mechanism and its ~NE-trending P-axis are consistent with focal mechanisms along the eastern seaboard, which generally have a NE-trending SHmax direction. The 2024 event likely represents a rare tectonic earthquake in the greater Florida region providing a ‘teachable moment’ to consider active tectonics in a very slowly deforming compressional regime.
Session: Earthquakes, Lithospheric Structure, and Dynamics in Stable Continental Region [Poster]
Type: Poster
Room: Exhibit Hall
Date: 4/17/2025
Presentation Time: 08:00 AM (local time)
Presenting Author: Jochen Braunmiller
Student Presenter: No
Invited Presentation:
Poster Number: 62
Additional Authors
Jochen Braunmiller Presenting Author Corresponding Author jbraunmiller@usf.edu University of South Florida |
Felix Rodriguez Cardozo felixr1@usf.edu University of South Florida |
Glenn Thompson thompsong@usf.edu University of South Florida |
Stephen McNutt smcnutt@usf.edu University of South Florida |
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The February 2024 M4.1 Earthquake Offshore Cape Canaveral, Florida
Category
Earthquakes, Lithospheric Structure, and Dynamics in Stable Continental Regions
Description