Marc Szeglat

Iceland: Eruption started suddenly

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The long-awaited eruption began on Iceland’s Reykjanes Peninsula yesterday evening. At 10:17 p.m. an approximately 4 km long eruption fissure opens between Stóra-Skógfell and the old Sundhnúkar crater series. Lava fountains shoot up to 100 m high. The delivery rate is estimated at 100 – 200 cubic meters per second. The flow speed is just under 1 km per hour. The distance from the southern end to the outskirts of Grindavík is almost 3 km.

The volcanic eruption was preceded by a seismic crisis that began 90 minutes before the eruption. The IMO tables show 538 shocks, the period again being 48 hours. A good 300 earthquakes occurred immediately before the eruption. If you look at the size of the fissure, there were very few earthquakes and the warning time was short. It can be assumed that the melt was less than 1 km below the surface. It had already risen to this depth shortly after the dyke intrusion on November 10th. Apparently later, the volcanologists’ assessments were incorrect that most of the melt in the dyke had solidified after just 2-3 weeks. There were probably no measurable magma movements because the pressure in the dyke was too great.

Stromboli with stronger eruption

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Yesterday, there was an eruption at the Sicilian island volcano Stromboli that was larger than normal. Footage shared on social media depicts an ash cloud drifting southward above the volcano. A stronger explosion signal is evident in the seismic activity. However, the explosion wasn’t strong enough to prompt the INGV to issue an extraordinary bulletin. Yesterday, the LGS confirmed that the emission of carbon dioxide was high, with over 1100 tons of this odorless gas being emitted. Most other geophysical measurement values remained at a moderate activity level, except for the sound pressure generated during the typical Strombolian eruptions, which was classified as low, measuring 0.26 bar. The volcanic activity was characterized by Strombolian explosions and degassing activities in the northeastern and southwestern sectors of the crater. The increased carbon dioxide emission suggests an increased ascent of magma from depth. A similar signal is coming from deep earthquakes in the asthenosphere region, which have been increasingly recorded in recent days. In a few months, we could therefore experience another phase of lava activity at Stromboli.

Earthquake caused by magma intrusion near Grindavik on Iceland

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There has been a strong swarm earthquake under Iceland’s Reykjanes Peninsula since October 25th. Several tremors had magnitudes in the region of five. The earthquakes were triggered by an accumulation of magma at a depth of 4-5 km and the ground rose. At the center of this uplift was the area around the Thorbjörn volcano near Svartsengi. On Friday November 10th, activity increased significantly and a dyke formed. It is 15 km long and runs from Kálffellsheiði on the northwest edge of Fagradalsfjall to under the sea near Grindavik. The place was evacuated because a major volcanic eruption is expected in the next few days.

Access to the area was cordoned off over a large area and a no-fly zone for drones was set up.

Strong earthquake swarm on the Icelandic Reykjanes Peninsula

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In the past few days, there has been a significant earthquake swarm on the Icelandic Reykjanes Peninsula. More than 7,500 tremors were recorded. The strongest earthquake had a magnitude of 4.9. These earthquakes were concentrated in an area northwest of the Thorbjorn volcano, specifically beneath the Svartsengi geothermal power plant. A rapidly progressing ground uplift of 3 cm has now been observed, which is caused by a magma accumulation underground. The ground has also risen in the Fagradalsfjall volcano area. Scientists from the Icelandic Meteorological Office (IMO) anticipate a new eruption. The Volcano Observatory Notice for Aviation (VONA) alert status has been raised to “Yellow.”

The strongest earthquake of the uplifting phase has shaken Campi Flegrei

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Date: 27.09.23 | Time: 03:35:34 UTC | Location: 40.8170; 14.1560 | Depth: 2.9 km | Magnitude: 4.2

Tonight a moderate earthquake of magnitude 4.2 occurred beneath the southern Italian Caldera volcano Campi Flegrei. It was the strongest earthquake of the current uplift period, which began in 2005. The hypocenter was at a depth of 2900 m. The epicenter was located on the coast in the area of Via Napoli between the towns of Pozzuoli and Bagnoli. The Solfatara is approximately 1300 meters northwest of the epicenter. The earthquake occurred at 03:35:34 UTC (05:35:34 local time) and is likely to have awakened some residents from their sleep. There have been no reports of damage so far, although despite the moderate magnitude, some houses may have developed cracks, as the earthquake’s hypocenter was shallow.

Lewotolok erupts ash clouds and glowing tephra

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The Lewotolok is a 1431-meter-high stratovolcano located on the Indonesian island of Lembata. It has been active for nearly three years, with only a few short periods of eruption pauses. During the summer, the eruptive activity was relatively low, with approximately 10 strombolian eruptions recorded per day. In the past week, the activity has significantly increased, and yesterday, the VSI (Volcanological Survey of Indonesia) detected 107 eruptions. These eruptions generated seismic signals with maximum amplitudes of 38 mm and durations of up to 358 seconds. The number of volcanically-induced earthquakes also increased, with 26 volcanic-tectonic tremors recorded yesterday. Additionally, there were 17 tremor phases. There were 155 signals originating from strong degassing, which was more prevalent during weeks of low eruptive activity than it is now. Up to 400 of these signals were recorded per day.

A new eruption began at Kilauea in Halema’uma’u Crater

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Yesterday afternoon, the Kilauea volcano erupted again. It started around 3:30 PM Hawaiian time when a 1400-meter-long eruption fissure opened in the summit caldera. It cut across the Halema’uma’u Crater and even intersected one of the blocks in the caldera that had subsided during the 2018 eruption. During the initial phase, lava fountains up to 50 meters high were produced. The lava quickly spread in the Halema’uma’u Crater, creating a large secondary lava lake that now covers most of the crater floor. An area noticeably higher than the rest of the flat crater floor remains uncovered. This area was active during the recent eruption and was built up by several layers of lava. Most of the activity along the eruption fissure has since ceased, with the majority of lava now bubbling up from a partial rift near the base of the crater wall, and some lava appears to be welling up in the opposite sector of the rift.

The volcanic eruption was not unexpected. For several weeks, there had been a significant increase in seismic activity, with daily records of between 150 and 200 minor tremors, primarily concentrated in an area south of the caldera. There were periods of significant ground uplift, which had subsided in the days leading up to the eruption. During that time, the magma that is erupting now had accumulated in a magmatic conduit.

Strong Earthquake Mw 6.9 Causes Casualties in Morocco

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Date 09/08/23 | Time: 22:11:00 UTC | 31.074; -8.477 | Depth: 10 km | Mw 6.9

A strong earthquake with a moment magnitude of 6.9 occurred last night near Agadir and Marrakesh. The earthquake occurred at 22:11:00 UTC. The quake caused significant destruction and has resulted in 632 fatalities and 329 injuries so far. The exact depth of the hypocenter varied depending on the source: EMSC reported a depth of 10 km, GFZ Potsdam measured 27 km, and USGS determined nearly 19 km. EMSC located the epicenter 60 km west-southwest of Oukaïmedene, in a remote region of the Atlas Mountains. There were severe damages, particularly in the mountain villages near the epicenter, where numerous buildings have completely collapsed. The search for victims is still ongoing, and in many areas, there have been power outages and communication disruptions. There is speculation that landslides may have occurred, and some communities could be isolated from the outside world.

Earthquake Mb 3.8 near Solfatara triggers swarm of earthquakes

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Date 09/07/23 | Time: 17:45:28 UTC | 40.83; 14.147 | Depth: 2.5 km | Mb 3.8

Yesterday, there was an earthquake in the Campi Flegrei Caldera with a magnitude of 3.8. The earthquake’s epicenter was at a depth of 2.5 km. The earthquake occurred near the northeastern crater rim of Solfatara, close to the thermal area of Piscarelli, and triggered an aftershock sequence with 30 subsequent earthquakes. These aftershocks mostly had low magnitudes in the microseismic range.

The main earthquake was felt in Pozzuoli and parts of Naples. EMSC received reports from people located 16 km away from the epicenter who felt the tremor. For those living closer, the earthquake was strong and frightening, but there are no reports of damage.

Explosion at Shishaldin sends ash up to 9,700 meters in height

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Yesterday afternoon, around 16:30 UTC (08:30 local time), an explosive eruption of the volcano Shishaldin began. It was preceded by several hours of increasing seismic activity. The explosion produced a large ash cloud that rose to an altitude of 9,700 meters and drifted southeastward over the sea. During the eruption, a high thermal radiation of 321 MW was recorded, indicating that not only volcanic ash but also red-hot lava was erupting. The eruption caused strong tremors, clearly visible on the seismogram.

Half an hour later, seismic activity rapidly decreased, and the altitude of ash emissions observed by satellite also reduced to about 4,500 meters. By 20:00 UTC, the ash cloud had spread about 125 km in low altitude.

Shishaldin is a 2,857 m high stratovolcano on the Aleutian Island of Unimak. The Aleutians are a volcanic island arc connected to the Alaska Peninsula.