Eruptions

News about eruptions and volcanoes can be found in this category. It is updated frequently. Volcano expert and journalist Marc Szeglat reports live from his expeditions to volcanoes.

Lahar occurred on Santiaguito volcano

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Heavy rains at the Santa Maria-Santiaguito volcanic complex triggered a lahar yesterday. The moderate mudflow initially followed the Cabello de Ángel stream and then merged into the Nimá I and Samalá rivers. Along with mud, volcanic rocks as large as one meter in diameter were carried by the water. Additionally, branches and tree trunks were swept away. The lahar generated a significant seismic signal that exceeded the scale and masked any volcanically-induced earthquake signals.

Lahars form when water mobilizes deposited volcanic ash on the volcano’s slopes. These mudflows have a high destructive potential and typically flow along drainage channels and riverbeds, but they can exit these paths and cause flooding. Survival chances are low if caught in a mudflow. Lahars are nearly as dangerous as pyroclastic flows, which can also occur at Santiaguito. The dome volcano on the flank of Santa Maria is active, building its lava dome. A viscous lava flow extends from the dome, flowing southwestward. Debris avalanches occur, and explosions propel volcanic ash up to 900 meters above the crater’s rim.

Kilauea with increased seismic activity

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Seismic activity is still high south of Hawaii’s Kilauea summit caldera. Yesterday, there were 250 small tremors in just 24 hours. In Hawaii, it’s now 8:00 PM on August 24th, and more than 150 earthquakes have been recorded so far. Though it’s unlikely to reach the previous day’s high count, earthquake activity remains elevated. Ground deformation is also increasing significantly, rebounding from a slight dip 2 days ago. Since last September, the ground has risen by about 65 cm, despite previous lava activity. The volcano’s magma chamber couldn’t be emptied enough to reduce the uplift. The erupted lava filled Halema’uma’u crater by 400 meters. A new graph shows current measurements of the crater’s depth using a laser rangefinder. This depth is measured against the point after the 2018 Leilani eruption collapse when the crater was at 518 meters above sea level.

Mount Dempo Volcano in Sumatra with phreatic eruption

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Yesterday, the VSI reported that there was an eruption at Mount Dempo volcano on Sumatra. A seismic signal was recorded, with a strong shaking that lasted for about 3 minutes. This signal was detected at 9:05 AM local time. At first, there was no visual confirmation of the eruption. However, a video showing the eruption was shared on the social media platform ‘X’ this morning.

Last year, there were signs that the volcano might become active again when there was a sudden burst of steam and gas in May. In January 2022, the alert level was raised to ‘yellow’ due to some shaking underground. There were some smaller eruptions at the end of July this year, but I missed them because I was traveling in Kenya. An ash cloud was seen rising up to 2 km above the volcano’s opening on July 25, 2023. There were also more earthquakes than usual on that day. It’s possible that the volcano is slowly getting ready for bigger eruptions.

Lavadome on Mayon remain active

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On the Philippine island of Luzon, Mayon continues to remain active, erupting a lava dome. Three lava flows emanate from the dome, flowing through the channels of Bonga, Mi-isi, and Basud, measuring 3.4 km, 2.8 km, and 1.1 km in length, respectively. Both lava flows and the dome are generating rock avalanches that leave glowing traces in nighttime images. Yesterday, 127 of these rock avalanches were recorded by seismographs. Additionally, signals from 6 pyroclastic flows were detected, resulting from larger collapse events and traveling up to 4 km. Ash clouds reached altitudes of up to 3 km. Mayon also remains seismically active, with 35 volcano-related earthquakes detected. Among these events, 20 were characterized as tremor signals, lasting for up to 80 minutes. Tremors are caused by fluid movements underground, indicating the presence of more magma in transit. This is further indicated by a high concentration of gaseous sulfur dioxide. In the last 24 hours, 1467 tons of this gas were emitted. A steam plume rose up to 700 m above the dome. The volcanic structure of Mayon is swollen, and inflation is occurring.

Mount Etna unexpectedly produced a paroxysmal eruption

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Paroxysm Mount Etna @fabrizio_zuccarello & @etnative

Once again, the spectacular scene of a paroxysmal eruption from the new Southeast Crater could be admired on Mount Etna. The eruption began in the evening around 8:30 PM UTC (Central European Summer Time +2 hours) with Strombolian activity from the volcano. This activity rapidly intensified, and just an hour later, ash clouds started to rise, reaching up to 1000 meters above the crater’s elevation, as reported by the Toulouse VAAC. The main phase of the paroxysm then began around 12:00 AM UTC and reached its peak around 1:20 AM UTC. During this phase, ash was ejected to a height of 6100 meters, and a lava fountain several hundred meters high illuminated the night sky over Sicily. By 3:20 AM UTC, the lava fountain collapsed, but ash continued to rise. An hour later, the ash reached a height of 8200 meters and drifted southward. The ash emissions ended around 5:50 AM UTC. The lava fountain activity was accompanied by a lava overflow, with the lava flow not heading into Valle del Bove but rather towards the southwest. This corresponds to the path from the vent in the new Southeast Crater that previous lava flows had taken.

Stromboli with further lava overflo

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Yesterday morning, another lava flow formed at Stromboli, spilling from a vent in the northeastern crater sector. Similar to previous episodes, there were no significant changes in geophysical parameters leading up to the increase in activity, except for a rise in tremor amplitude. The accompanying graph shows a corresponding peak reaching into the lower red range, although it didn’t reach the value of the previous episode, which was accompanied by a stronger explosive eruption. Photos document that the current episode was also marked by lively Strombolian activity and lava spattering. The activity began increasing during the morning hours. By noon, the lava flow was only 100 meters long. Rock avalanches originated from its front.

Lava dome at Mayon is growing

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Mayon volcano on Luzon island in the Philippines remains active, building up its lava dome. It has produced three lava flows, the longest of which has traveled a distance of 3.4 km. These flows follow the channels of Bonga, Mi-isi, and Basud. Yesterday, seven pyroclastic density currents were reported, covering a distance of up to 4 km. Additionally, 201 debris avalanches were recorded. An ash eruption was also observed, sending volcanic ash up to an altitude of 3000 m.

The seismic network of PHILVOLCS detected 100 volcano-related earthquakes. Among these, 58 were tremor phases caused by magma movements underground. Some of these tremors lasted up to 13 minutes, suggesting that the volcano does not intend to decrease its activity in the near future.

Gas emissions reached 1888 tons per day yesterday, which is a significant amount. Steam rose up to 800 m above the height of the dome.

Overall, ground deformation due to magma inflation is being observed. However, in the eastern part of the volcanic area, the opposite trend of deflation is occurring. It’s likely that the magma erupting at the dome currently originates from this sector.

Mayon is an active stratovolcano located on the island of Luzon in the Philippines. It is known for its nearly perfect cone shape and is one of the most iconic and picturesque volcanoes in the country.

Fuego erupts ash up to 5200 m altitude

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In Guatemala, the Fuego volcano has become more active again compared to the past few weeks. Today, the VAAC issued a VONA warning stating that volcanic ash has risen up to an altitude of 5200 m. The wind has carried the ash cloud in a western direction, leading to ashfall in the communities in that direction.

The volcanologists from INSIVUMEH released their observations in a daily update yesterday. They reported 5 to 8 eruptions per hour on the previous day, with ash clouds reaching an altitude of up to 4700 m. The ash has shifted up to 15 km to the west, causing light ashfall in areas such as Finca Palo Verde, Sangre de Cristo, San Pedro Yepocapa, and Acatenango.

Karangetang with numerous rock avalanches

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The dome in the southern crater of the Indonesian volcano Karangetang continues to grow, and numerous rock avalanches are occurring, leaving glowing traces in nighttime images. There are also signs of a sluggish lava flow making its way down the southern flank. On long-exposure photos, the glowing traces of the rock avalanches are not always distinguishable from lava flows. A daytime image shows bluish gas emissions emanating from the flank, indicating a lava flow. A satellite photo from August 1st reveals two thermal anomalies in the infrared range, possibly originating from lava flows. The distinction between rock avalanches and lava flows is uncertain here as well.

Larger explosion and lava flow at Stromboli

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Yesterday evening at 7:06 PM, an explosive eruption occurred, which was stronger than the everyday eruptions at Stromboli. This is indicated by a report from INGV. The entire crater terrace was covered with tephra. However, according to current knowledge, there were no impacts of larger blocks or bombs on Pizzo or along the Cima, where tourists were previously allowed. In connection with the explosion, two lava overflows also occurred from the northern crater area. The lava fronts quickly reached the upper part of the Sciara del Fuoco. Similar lava overflows had already been observed in the past few days. At that time, the activity was accompanied by lava spattering. I already pointed out last week that lava flows on Stromboli usually form in phases. During such phases, there is also an increased danger of stronger explosions and paroxysms, which can even generate pyroclastic flows extending to the sea.