Solving a Seismic Mystery With the Audio From a Diver's Camera: A Case of Shallow Water T‐Waves in the Persian Gulf.

Sparse offshore coverage of seismic networks has hindered detailed studies of submarine earthquakes and their associated seismic hazard. We present results of our analysis of a diver's recording of acoustic signals from an ML = 5.6 earthquake in the Persian Gulf. We model the signals as a set of several shallow water T phases the frequency and group velocity of which are determined by bathymetry. We show that the audio track from this recording can provide reliable estimates of earthquake location and seismic moment. We also show that the reported shaking in the southern Persian Gulf, >170 km from the source of this small earthquake could result from T waves traveling through the entire width of the basin. Our results point to rudimentary and affordable underwater microphones similar to those used in the divers' cameras as tools to build efficient, low‐cost networks for the study of offshore events and early warning. Plain Language Summary: The lack of offshore seismic stations or the low population of such networks has caused our knowledge of near‐shore earthquake sources to be incomplete. To this end, and as a possible tool to study the source of submarine earthquakes, we have analyzed the video recording from a group of divers who have captured the moments during an earthquake in the Persian Gulf region. This earthquake which occurred on the northern, Iranian side of the Persian Gulf was strongly felt along its southern shorelines, more than 170 km from the epicenter. The analysis of this video, which surfaced on social media, points to a set of trapped acoustic signals in the water, or T‐waves, in close proximity of the source. We show that such recordings can be reliably used to obtain important information regarding the earthquake source, including its location and magnitude. Besides, we make the case that the reported shaking in Dubai was likely due to the arrival of such high‐pitch T‐ waves from the earthquake. Finally, we propose that cheap microphones existing in standard entertainment cameras can be used to build efficient underwater networks for monitoring small to moderate offshore events. Key Points: We use a diver's camera recording to study an offshore, moderate earthquake in the Persian GulfA propagation model and simulations of shallow water T‐waves are presentedLow‐cost, entertainment‐quality, subsea hydrophones run by citizen scientists can augment monitoring of offshore events [ABSTRACT FROM AUTHOR]