SERNAGEOMIN reported that during 1-16 February the seismic network at Laguna del Maule recorded a total of 533 volcano-tectonic earthquakes.
Two earthquake swarms were recorded during 15-16 February; the largest events were local magnitude 3.1, and were located 9.1 and 8.8 km SW of the lake at a depth of 1.9 km.
The epicenters were near the area producing anomalous carbon dioxide emissions.
Swarms were recorded in June and December 2020, and January and February 2021, with the largest events occurring during the most recent swarm.
The highest rate of inflation during the previous 30 days was 2.3 cm/month, recorded at a station closest to the center of deformation.
The highest horizontal displacement was an estimated 1.4 cm/month from a station just SW of the center.
InSAR data mostly showed agreement in the magnitude and distribution of the ground-based deformation data.
Overall, the deformation rates were higher than maximum averages.
On 22 February the Alert Level was raised to Yellow, the second lowest level on a four-color scale.
ONEMI declared a Yellow Alert for San Clemente and recommended restricted access within a radius of 2 km from the center of elevated carbon dioxide emissions.
Sources: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI) ,Servicio Nacional de Geología y Minería (SERNAGEOMIN)