The Weekly Volcanic Activity Report: July 9–15, 2025
New activity/unrest was reported for 7 volcanoes from July 9 to 15, 2025. During the same period, ongoing activity was reported for 18 volcanoes.
Eruptive activity at Sundhnúk crater row continues at decreased intensity, Iceland
While the eruption at the Sundhnúksgígar crater row, southeast of Litla-Skógfell, Iceland continues on July 18, 2025, the eruptive activity has declined in the last 24 hours.
Peru’s ‘smallest volcano in the world’ identified as baby mud volcano
The Peruvian Geophysical Institute investigated a mound near Songoña in the Cusco region, dubbed the ‘smallest volcano in the world’ by local media, and confirmed it as a small mud volcano.
New volcanic eruption opens 1 km-long fissure southeast of Litla-Skógfell, Iceland
A fissure eruption began at the Sundhnúksgígar crater row, southeast of Litla-Skógfell, Iceland, around 03:54 UTC on July 16, 2025. The eruptive fissure is approximately 700–1 000 m (2 300–3 280 feet) long and appears to be propagating northward, with lava flowing southeast and no immediate threat to infrastructure.
Sudden eruption produces dense ash plume at Erta Ale volcano, Ethiopia
A sudden explosive eruption at Erta Ale volcano in Ethiopia’s Danakil Depression produced a dense ash plume on the morning of July 15, 2025, interrupting its recent phase of steady lava activity.
Powerful phreatic eruption at Santa Teresa ausol blocks road in Ahuachapán, El Salvador
A powerful phreatic eruption occurred at the Santa Teresa ausol, part of the Los Ausoles geothermal field in Ahuachapán, El Salvador on July 10, 2025. The eruption ejected a column of boiling water, steam, and sediment, blocking an access road and damaging surrounding infrastructure. No injuries were reported.
The Weekly Volcanic Activity Report: July 2–8, 2025
New activity/unrest was reported for 3 volcanoes from July 2 to 8, 2025. During the same period, ongoing activity was reported for 18 volcanoes.
Glacial outburst flood developing at Mýrdalsjökull, Iceland
A glacial outburst flood has been developing in the Leirá syðri and Skálm rivers, southern Iceland, following rising water levels and electrical conductivity measured since July 7, 2025. Conditions continued to intensify as of 15:00 LT on July 9.
Shallow seismic swarm underway in the Michoacán–Guanajuato Volcanic Field, Mexico
More than 440 earthquakes have been recorded since June 17, 2025, within the Michoacán–Guanajuato Volcanic Field, specifically in the Tancítaro–Parícutin region of Michoacán, Mexico, in an ongoing seismic swarm associated with magmatic activity. The last eruptive period in the field occurred from 1943 to 1952 (VEI 4).
Earthquake swarm detected beneath Mount Rainier, Washington
A swarm of hundreds of small earthquakes was detected beneath the summit of Mount Rainier, Washington, starting at 01:29 LT (08:29 UTC) on July 8, 2025, prompting increased monitoring by the USGS Cascades Volcano Observatory and the Pacific Northwest Seismic Network.
