The rupture plane of the February 2022 Mw 6.2 Guatemala, intermediate depth earthquake

Abstract

An intermediate depth intraplate earthquake with Mw 6.2 was generated in the Guatemalan subduction zone on 16 February 2022 with epicenter to Southwest of the department of Escuintla. More than 275 aftershocks were registered, which were relocated with the HypoDD algorithm, being able to identify a fault with an area of ~350 km2, which is considerably higher than expected for an earthquake of that magnitude. The moment tensor at the centroid of the main earthquake and the estimation of other focal mechanisms of the largest aftershocks, allowed us to identify extension earthquakes, related to the fault plane, and compression earthquakes that were associated with seismicity on the upper part of the slab. The region of the sequence has presented high seismic activity in recent years. It is proposed that the mainshock nucleated in the lower seismicity layer (LSL) of the double seismicity zone proposed for the region, triggering seismic activity on a pre-existing active fault, also triggering seismic activity in the upper seismicity layer (USL). The separation between these seismicity layers was estimated to be 12.2±5.0 km.

Keywords

• intermediate depth earthquake
• seismic hazard in Guatemala
• earthquake relocation