In the Panama Basin, ~80 km off the west coast of Colombia (5.0°N, 78.1°W) and within the Nazca plate, unexpectedly deep earthquakes (~70-90 km) have been recorded. The earthquakes are unexpected because the high pressure and temperature at these depths should prevent brittle failure and therefore earthquakes, especially in the young, warm crust (9-12 Ma) in this region. In order to explore possible causes of the earthquakes, their depths must first be confirmed. Earthquakes from the Colombian National Seismic Network from January 2010 to July 2019 were relocated relative to other nearby earthquakes to better determine the earthquakes’ latitude, longitude, and depth. From 4°-6°N, 77°-79° W, and 25-90 km depth, 270 earthquakes were relocated. Three earthquakes (~5.0°N, ~78.1°W) had depths between 70-90 km and relatively small depth errors (10-15 km). The deep depths were robust with respect to the velocity model and variations in other relocation parameters. To further confirm the depths, the seismic waveforms from these events were then compared to those of shallow events in the same area. The unexpectedly deep earthquakes may be caused by: a microplate to the north, the formation of a new subduction zone, or a proposed slab tear to the east.

Adrea would like to thank Dr. Warren for her support and guidance throughout Adrea's time at SLU.