Global Volcanic Activity – New Activity for the week of 11 September – 17 September 2019
Alaid | Kuril Islands (Russia) : The Tokyo VAAC reported that on 11 September an ash plume from Alaid identified in satellite images rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SE.
Copahue | Central Chile-Argentina border : OVDAS-SERNAGEOMIN reported that a long-period (LP) earthquake at Copahue recorded at 1657 on 11 September correlated with an infrasound signal from an explosion; a gas-and-ash emission rose to low heights. A larger explosion, recorded at 2245 along with an LP earthquake, produced a plume that rose 250 m above the crater rim. Incandescent deposits around the vent were visible at night, and a 3-km-long ash deposit, covering an area of 3.4 square kilometers, was visible on the ESE flank. The Alert Level remained at Yellow (second lowest level on a four-colour scale); SERNAGEOMIN recommended no entry into a restricted area within 500 m of the crater. ONEMI maintained the Alert Level at Yellow (the middle level on a three-colour scale) for the municipality of Alto Biobío.
Nevados de Chillan | Chile : ONEMI and SERNAGEOMIN reported that during 10-17 September white-to-gray gas plumes from Nevados de Chillán’s Nicanor Crater rose 400-800 m above the rim and drifted NE, E, and SE. Explosions sometimes ejected incandescent material onto the E and SE flanks. A lava flow on the NNE flank was 100 m wide, 5 m thick, and had advanced 600 m by 14 September. The Alert Level remained at Orange, the second highest level on a four-colour scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the communities of Pinto, Coihueco, and San Fabián, and stated that the public should stay at least 3 km away from the crater on the SW flank and 5 km away on the ENE flank.
Villarrica | Chile : Video from an 11 September overflight of Villarrica, conducted by the Carabineros Región de La Araucanía, showed an active cone on the crater floor. ONEMI and SERNAGEOMIN noted that the activity was consistent with the elevated seismicity detected by the seismic network during the previous few days. Seismicity and explosive activity in the crater both began decreasing on 12 September and continued a downward trend at least through 16 September. Discrete tremor signals disappeared during 15-16 September, with moderate levels of continuous tremor dominating the signal. No explosions were detected. SERNAGEOMIN lowered the Alert Level to Yellow, the second lowest level on a four-colour scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the municipalities of Villarrica, Pucón (16 km N), Curarrehue, and the commune of Panguipulli, and changed the exclusion zone for the public to a radius of 1 km around the crater.