Report on Erta Ale (Ethiopia) — October 2020
Bulletin of the Global Volcanism Network, vol. 45, no. 10 (October 2020)
Managing Editor: Edward Venzke. Edited by Kadie L. Bennis.
Erta Ale (Ethiopia) Thermal anomalies persist in the summit crater during May-September 2020
Please cite this report as:
Global Volcanism Program, 2020. Report on Erta Ale (Ethiopia) (Bennis, K.L., and Venzke, E., eds.). Bulletin of the Global Volcanism Network, 45:10. Smithsonian Institution.
13.6°N, 40.67°E; summit elev. 613 m
All times are local (unless otherwise noted)
Erta Ale is an active basaltic volcano in Ethiopia, containing multiple active pit craters in the summit and southeastern caldera. Volcanism has been characterized by lava flows and large lava flow fields since 2017. This report describes continued thermal activity in the summit caldera during May through September 2020 using information from various satellite data.
Volcanism at Erta Ale was relatively low from May to early August 2020. Across all satellite data, thermal anomalies were identified for a total of 2 days in May, 7 days in June, 4 days in July, 11 days in August, and 15 days in September. Beginning in early June and into September 2020 the Sentinel-2 MODIS Thermal Volcanic Activity graph provided by the MIROVA system identified a small cluster of thermal anomalies in the summit area after a brief hiatus from early January 2020 (figure 99). By mid-August, a small pulse of thermal activity was detected by the MIROVA (Middle Infrared Observation of Volcanic Activity) system. Many of these thermal anomalies were seen in Sentinel-2 thermal satellite imagery on clear weather days from June to September.
|Figure 99. A small cluster of thermal anomalies were detected in the summit area of Erta Ale (red dots) during June-September 2020 as recorded by the Sentinel-2 MODIS Thermal Volcanic Activity data (bands 12, 11, 8A). Courtesy of MIROVA.|
On 12 June a minor thermal anomaly was observed in the S pit crater; a larger anomaly was detected on 17 June in the summit caldera where there had been a previous lava lake (figure 100). In mid-August, satellite data showed thermal anomalies in both the N and S pit craters, but by 5 September only the N crater showed elevated temperatures (figure 101). The thermal activity in the N summit caldera persisted through September, based on satellite data from NASA VIIRS and Sentinel Hub Playground.
Geologic Background. Erta Ale is an isolated basaltic shield that is the most active volcano in Ethiopia. The broad, 50-km-wide edifice rises more than 600 m from below sea level in the barren Danakil depression. Erta Ale is the namesake and most prominent feature of the Erta Ale Range. The volcano contains a 0.7 x 1.6 km, elliptical summit crater housing steep-sided pit craters. Another larger 1.8 x 3.1 km wide depression elongated parallel to the trend of the Erta Ale range is located SE of the summit and is bounded by curvilinear fault scarps on the SE side. Fresh-looking basaltic lava flows from these fissures have poured into the caldera and locally overflowed its rim. The summit caldera is renowned for one, or sometimes two long-term lava lakes that have been active since at least 1967, or possibly since 1906. Recent fissure eruptions have occurred on the N flank.
Information Contacts: MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground); NASA Worldview (URL: https://worldview.earthdata.nasa.gov/).