5:15 PM - 6:45 PM
[SCG40-P25] Shallow tectonic tremor triggered by large regional earthquakes in the southeastern Guerrero seismic gap
Slow earthquakes can trigger large earthquakes and can be triggered by large earthquakes. Monitoring slow earthquake activity may help us reach forecasts of large earthquakes. Accurately calculating the source of tectonic tremors provides essential information for comprehending the spatial features hosting slow earthquakes by comparing them with other information about the crustal structure, such as seismic velocity and gravity anomaly.
Along the Pacific coast of Mexico, large earthquakes frequently occur due to the subduction of the Cocos Plate beneath the North American Plate. However, a seismic gap exists offshore Guerrero, where megathrust earthquakes have not happened in the past 100 years (e.g., Kostoglodov et al., 2001). Based on the records observed by ocean bottom seismometers in the northwestern part of the Guerrero seismic gap from 2017 to 2018, Plata-Martinez et al. (2021) figured out the spatial pattern of slow and fast earthquakes. They discussed the relation to residual gravity and bathymetry profile in the northwestern Guerrero seismic gap.
This study investigates tectonic tremor activity in the southeastern Guerrero seismic gap with seismograms from 8 ocean bottom seismometers installed from March 2022 to March 2023. We apply the modified envelope correlation method (Mizuno and Ide, 2019) to detect and locate tectonic tremor sources. We changed the grid interval to use this method for the station network in the southeastern part of the gap. The distribution of tectonic tremors forms some clusters, and we discuss the characteristics of each cluster. We also examine the change in the distribution of tectonic tremors according to their duration. During the observation period, three earthquakes larger than M6 occurred. One occurred near the observation network, and the others occurred approximately 300 km away from the stations. Considering residual gravity and bathymetry profile, we also analyze the relationship between these three earthquakes and tectonic tremors.
Along the Pacific coast of Mexico, large earthquakes frequently occur due to the subduction of the Cocos Plate beneath the North American Plate. However, a seismic gap exists offshore Guerrero, where megathrust earthquakes have not happened in the past 100 years (e.g., Kostoglodov et al., 2001). Based on the records observed by ocean bottom seismometers in the northwestern part of the Guerrero seismic gap from 2017 to 2018, Plata-Martinez et al. (2021) figured out the spatial pattern of slow and fast earthquakes. They discussed the relation to residual gravity and bathymetry profile in the northwestern Guerrero seismic gap.
This study investigates tectonic tremor activity in the southeastern Guerrero seismic gap with seismograms from 8 ocean bottom seismometers installed from March 2022 to March 2023. We apply the modified envelope correlation method (Mizuno and Ide, 2019) to detect and locate tectonic tremor sources. We changed the grid interval to use this method for the station network in the southeastern part of the gap. The distribution of tectonic tremors forms some clusters, and we discuss the characteristics of each cluster. We also examine the change in the distribution of tectonic tremors according to their duration. During the observation period, three earthquakes larger than M6 occurred. One occurred near the observation network, and the others occurred approximately 300 km away from the stations. Considering residual gravity and bathymetry profile, we also analyze the relationship between these three earthquakes and tectonic tremors.