ONEMI and SERNAGEOMIN reported that the seismic network at Villarrica recorded significant variations in seismicity beginning at 0030 on 8 September, characterized by an increase in the number of long-period (LP) events from 20 to 50 per hour.
LP events ceased to be detected around 1030 and short periods of high-energy tremor began.
Weather clouds prevented views of the summit crater, though the characteristics of the seismicity indicated fluctuating lava-lake activity.
The increased seismicity persisted on 9 September, prompting SERNAGEOMIN to raise the Alert Level to Orange, the second highest level on a four-color scale.
ONEMI has maintained an Alert Level Yellow (the middle level on a three-color scale) since 6 August for the municipalities of Villarrica, Pucón (16 km N), and Curarrehue, along with the commune of Panguipulli and stated that the public should stay at least 2 km away from the crater.
On 10 September seismicity remained high; infrasound signals were recorded at a rate of 50 events per hour.
Sources: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI) ,Servicio Nacional de Geología y Minería (SERNAGEOMIN)