The Salina cluster is named for the town of Salina Cruz on the coast of
Oaxaca, Mexico. About half the cluster is in the neighboring state of
Chiapas or offshore of it, including the 8.2 Mw Tehuantepec earthquake
of September 8, 2017. The cluster also includes three M6 events, on July
6, 2007 (6.0 Mw), December 17, 2015 (6.6 Mw) and September 23, 2017 (6.0
Mw) and a large number of earthquakes in the magnitude 5 range. Because
of the geometry of the coastline and location of the subduction zone,
most of the epicenters on land are subcrustal. Depths range from
approximately 10 to 160 km. All events have depth control from
near-source and local-distance readings, and most also have depth
constraint from teleseismic depth phases that is in close agreement. The
distribution of seismograph stations in the area is such that a
relatively large area needs to be included in order to ensure adequate
azimuthal coverage for location calibration.
