On 24 March OVDAS-SERNAGEOMIN reported that during an overflight of Nevados de Chillán scientists observed a single 100-m-diameter crater, the result of two active craters merging together sometime between 7 and 15 March.
In addition there were five explosions in the period of about an hour, ejecting tephra 900 m high which dispersed SE.
The pattern of activity changed on 17 March with increased frequency and magnitude of the explosions.
The Alert Level remained at Yellow, the middle level on a three-color scale, and the public was reminded not to approach the craters within a 3-km radius.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)