May 20 , 2025 .

Indonesia , Lewotobi Laki-laki :

An eruption of Mount Lewotobi Laki-laki occurred on Monday, May 19, 2025, at 9:52 PM WITA, with an observed ash column height of ± 4,000 m above the peak (± 5,584 m above sea level). The ash column was observed to be gray in color with a thick intensity, oriented toward the west and northwest. This eruption was recorded on a seismograph with a maximum amplitude of 47.3 mm and a duration of 180 seconds.

SPECIAL REPORT ON THE LATEST ERUPTION OF MOUNT LEWOTOBI LAKI-LAKI, MAY 18, 2025

The Lewotobi Laki-laki volcano in East Nusa Tenggara once again exhibited volcanic activity, with several eruptions occurring from 11:29 WITA to 13:47 WITA.

The eruption produced an ash column 3,000 to 5,500 meters high above the mountain’s summit, or about 7,000 meters above sea level. The observed eruptive column was dark gray in color and directed toward several points around the mountain’s slopes. The eruption was accompanied by a low- to moderate-intensity rumble, heard from the nearest monitoring station.

However, according to monitoring data from the past two weeks, no significant increase in seismic activity has been detected. Deep volcanic earthquakes, surface earthquakes, and local tectonic earthquakes were recorded in normal numbers and intensity. However, some recorded volcanic earthquakes had large amplitudes that would have triggered an increase in the height of the eruptive column.

Until this news was written, eruptive activity was still ongoing. Ash was reportedly being emitted continuously in bursts, indicating unstable volcanic activity. Residents around the mountain are urged to remain vigilant and follow the instructions of authorities and volcano monitoring agencies.

Sources : PVMBG , Magma Indonésie .

Photo : Magma Indonésie .

Argentina / Chile, Planchón-Peteroa Volcanic Complex:

For the period evaluated, a decrease in the number of volcano-tectonic (VT) events, associated with rock fracturing within the volcano, was observed compared to the previous period, while maintaining energy levels relative to the same period.
The highest-energy VT event recorded had a local magnitude (LM) of 2.4 and was located 12.4 km north-northwest (NNW) and 4.7 km deep, relative to the active crater.

Seismic activity associated with fluid movement within the volcano, represented by long-period (LP) events, recorded a slight increase in quantity and energy release compared to the previous period. The highest-energy event recorded showed a maximum reduced displacement (DR) of 1 cm².
IP cameras installed near the volcano did not detect any surface activity.

Satellite data processing did not reveal any anomalies in atmospheric sulfur dioxide (SO2) emissions in areas near the volcanic eruption.
Morphological analysis using PlanetScope and Sentinel 2 L2A satellite images revealed no variations attributable to volcanic activity.
Satellite image processing did not detect any thermal anomalies during the period under review.
Information from GNSS stations does not reveal any distortion in its horizontal or vertical components.

The affected area is considered to be the area near the crater with a radius of 800 m.
The green technical alert level indicates that the volcano is active, with stable behavior, but this does not indicate an immediate risk.

Source et photo : Segemar .

Costa Rica , Poas :

Daily Volcano Status Report Date: May 19, 2025, updated at: 11:05:00.

Latitude: 10.2
Longitude: -84.233
Elevation: 2,687 meters

Observed Activity:
An eruption occurred at 4:08 AM, with an ash column reaching approximately 1 km above the crater level.
The eruption was preceded by a cessation of acoustic tremor approximately 25 minutes earlier.
Aside from this observation, no other significant changes were observed in pre-eruption monitoring parameters.
Based on satellite imagery, it is estimated that 650 tonnes of SO2 were emitted yesterday.

Environmental Conditions:
Northeast winds

Activity Level: Caution (3)

Source : Ovsicori .

Photo : RSN-UCR. Capture d’écran 18 / 05 / 2025

United – States , California Volcanoes :

CALIFORNIA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Tuesday, May 13, 2025, 9:16 AM PDT (Tuesday, May 13, 2025, 16:16 UTC)

Current Volcano Alert Level: all NORMAL
Current Aviation Color Code: all GREEN

Activity Update:
All volcanoes monitored by CalVO show normal background earthquake activity and deformation. Monitored volcanoes include Mount Shasta, Medicine Lake Volcano, Lassen Volcanic Center, Clear Lake Volcanic Field, Long Valley Volcanic Region, Coso Volcanic Field, Ubehebe Craters, and Salton Buttes.

Past Week Observations for May 05 (0000h PDT) to May 11 (2359h PDT):

Typical seismicity was recorded at The Geysers geothermal field south of the Clear Lake Volcanic Field; 86 earthquakes greater than M1 were recorded, with the largest having a magnitude of M2.8.

One earthquake greater than M1 was recorded in the Mono-Inyo area north of Long Valley, with a magnitude of M2.1.

Five earthquakes greater than M1 were recorded in the Sierra Nevada Block, south of Mammoth Mountain and Long Valley, with the largest having a magnitude of M2.6.

Seven earthquakes greater than M1 were recorded in the Coso Volcanic Field, with the largest having a magnitude of M1.9.

Five earthquakes greater than M1 were recorded near the Salton Buttes, with the largest having a magnitude of M1.4.

CalVO’s Weekly Update only highlights volcanoes which have experienced seismic activity or volcanic unrest. If there are no comments for a volcano, CalVO has detected no earthquakes with magnitudes greater than or equal to M1.0, or any other kind of unrest. Only earthquakes with magnitudes greater than M1.0 are reported here.

Source : Calvo

Photo : Ubehebe crater / USGS

Guatemala , Santiaguito :

Weather conditions: Clear.
Wind: East.
Precipitation: 15.0 mm

Activity:
The Santa María-Santiaguito Volcanic Complex Observatory reports atmospheric conditions that are somewhat unfavorable for observing Dome Caliente due to cloud cover. Degassing is occurring, raising columns of magmatic gas.

Between one and two weak to moderate explosions per hour are reported, which also generate columns of gas accompanied by ash, which can reach heights of 800 meters above the crater level. The latter are moved westward by the wind direction, which is why light ashfall is expected on Monte Bello, Loma Linda, Monte Maria and the surrounding areas. Activity remains high, so it is possible that due to explosions or the effects of gravity, some of the accumulated material could collapse and generate large-scale pyroclastic flows towards the southwest, south and southeast. For these reasons, the recommendations described in special bulletin BESAN-002-2025 should be followed.

Source : Insivumeh .

Photo : Annie Winson , earthobservatory.sg