Report on Sabancaya (Peru) — 18 November-24 November 2020
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 18 November-24 November 2020
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2020. Report on Sabancaya (Peru). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 18 November-24 November 2020. Smithsonian Institution and US Geological Survey.
15.787°S, 71.857°W; summit elev. 5960 m
All times are local (unless otherwise noted)
Instituto Geofísico del Perú (IGP) and Instituto Geológico Minero y Metalúrgico (INGEMMET) reported that seismicity at Sabancaya had increased on 11 November. During the following week, the number and magnitude of explosions increased, and crater incandescence was visible in satellite and webcam data. The increased activity likely signified lava effusion, and a new lava dome in the NE part of the summit crater was confirmed in satellite images on 16 November. The dome, named Iskay, was 110 x 130 m in dimension and about 12,000 square meters in area. An IGP scientist noted that the dome was 78% smaller than the dome that had formed at the end of 2019.
A daily average of 49 explosions was recorded during 16-22 November. Gas-and-ash plumes rose as high as 3.5 km above the summit and drifted in multiple directions; ashfall was reported in the Huanca district on 22 November. Thirteen thermal anomalies over the crater were identified in satellite data. Minor inflation continued to be detected in areas N of Hualca Hualca (4 km N) and on the SE flank. The Alert Level remained at Orange (the second highest level on a four-color scale) and the public were warned to stay outside of a 12-km radius.
Geologic Background. Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning "tongue of fire" in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of historical eruptions date back to 1750.