[Vulkanen] The Ring of Fire #8: Het rommelt en borrelt

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Strong and shallow M5.6 earthquake, numerous aftershocks at Taupō volcano, New Zealand

Seismic unrest continues at Taupō volcano, New Zealand, with a strong and shallow M5.6 earthquake and numerous aftershocks registered on November 30, 2022. The Volcanic Alert Level for Taupō volcano was increased to Level 1 on September 20, 2022. This was based on ongoing earthquakes and deformation at levels above typical background since May.

Lake Taupō is a large caldera volcano, a special type of volcano that has rare but unusually large eruptions
The last eruption of this volcano took place in 260 CE
The quake hit at 10:47 UTC (23:47 LT) on November 30 at a depth of 5 km (3.1 miles), according to data provided by GeoNet.1 EMSC registered it as M5.4 at a depth of 1 km (0.6 miles).2

11 people reported extreme shaking, 69 severe, 5523 strong, and 1 151 moderate.

The rate of earthquake activity has varied since the increase started in May. After a peak of about 30 – 40 events per week from June to September, the number of earthquakes dropped over the last month to about 10 – 12 per week, GeoNet Duty Volcanologist Paul Jarvis noted on November 17.3

The number has now risen again, over the last two weeks, to a little over 20 events per week, Jarvis said.

GeoNet has located 840 earthquakes since the start of 2022, mainly at depths from 4 to 13 km (2.5 – 8 miles) beneath the center of Lake Taupō.

“We interpret the ground deformation and earthquake activity to be caused by activity associated with magma and hydrothermal fluids inside the volcano,” Jarvis said.

“This activity could continue for the coming weeks or months at varying rates or intensities. While some of the earthquakes have been felt in areas around Lake Taupō, the deformation is currently only detectable by our sensitive ground-based monitoring instruments.”

In broad terms, such volcanic unrest occurs when magma or magma-heated hot water and steam moves deep within the ground beneath a volcano, changing the stresses there and producing earthquakes and ground movement. There have been 17 previous episodes of unrest at Taupō over the past 150 years and none have resulted in an eruption, Jarvis noted.

The Volcanic Alert Level (VAL) was raised to Level 1 for Taupō Volcano on September 20, 2022. This was based on the current data but was also supported by new knowledge from research programs on volcanic eruptions and unrest at Taupō Volcano.

While Volcano Alert Level 1 is mostly associated with environmental hazards, the potential for eruption hazards also exists.

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STROMBOLI - De vulkaan Stromboli op het gelijknamige Italiaanse eiland is uitgebarsten. Daarvan gaan beelden rond op social media. Er zijn vooralsnog geen slachtoffers gevallen en er is ook nog geen noemenswaardige schade gemeld.

Eerder op de dag kwamen er al meldingen over een aardbeving. Niet veel later zou een luide explosie te horen zijn geweest en er is veel rookontwikkeling. De rook is vanaf omliggende eilanden goed te zien. Daarnaast zouden er ook pyroclastische stromen en mogelijk zelfs lava zijn waargenomen. De uitbarsting is bevestigd door het Italiaanse Instituut voor Geofysia en Vulcanologie en het Italiaanse persbureau ANSA. De lokale overheid heeft een tsunami-waarschuwing uitgegeven, volgens ANSA zou het gaan om een golf van anderhalf meter hoog.

Modderstromen en overstromingen op Sicili� door noodweer
Itali� is vaker toneel van vulkaanuitbarstingen, aangezien het land ligt tussen de Euraziatische en Afrikaanse plaat. De Etna, op Sicili�, barstte in februari 2022 nog uit. Een van de bekendste vulkaanuitbarstingen in het huidige Itali� was die van de Vesuvius in het jaar 79, waardoor de Romeinse stadjes Pompeii en Herculaneum onder een dikke laag as werden bedolven.

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Op dinsdag 6 december 2022 14:36 schreef Scrummie het volgende:
Is het de laatste tijd nou erg onrustig wat betreft vulkanen of gewoon meer dan normaal in het nieuws?

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Volcanic activity increases worldwide

Dec. 6 (UPI) -- As Hawaii's Mauna Loa and neighboring Kilauea volcanos simultaneously erupt, drawing worldwide attention, geologists are seeing increased volcanic activity across the globe.

Currently, there are 47 volcanoes around the world that are in "continuing eruption status," according to the Smithsonian Institution's Global Volcanism Program. That is more than double the normal number of what are called "continuing" volcanic eruptions, which are intermittent eruptions without a break of more than three months.

Most of the continuously erupting volcanos are clustered around what is called the "Ring of Fire," which circles the Pacific Ocean. According to the United States Geological Survey, most earthquakes and volcanic eruptions occur where the Pacific Plate meets many surrounding tectonic plates. The "Ring of Fire" is the most seismically and volcanically active zone in the world.

United States

Mauna Loa and Kilauea are currently erupting at the same time for the first time since 1984. They are just two of the 47 active volcanos actively erupting around the world. Mauna Loa, which is the largest active volcano on Earth, is erupting for the first time in 38 years. Kilauea was already active.

On Saturday, the Hawaiian Volcano Observatory, a division of the USGS, announced it had added webcams showing a livestream of lava erupting from Fissure 3 on the northeast rift zone of Mauna Loa.

On Tuesday, Hawaii deployed the National Guard, as Mauna Loa's lava flow moved closer to the Daniel K. Inouye Highway two weeks after it started erupting.

Hawaii deploys National Guard for Mauna Loa eruption
"Lava diversion is a tricky thing to do, especially on flat ground," said Hawaii County Civil Defense Administrator Talmadge Magnoe. "It really comes down to a volume problem. What we're seeing now is -- take 10 of the biggest dump trucks you can think of, we're getting that many dump trucks of lava every second delivered by this lava flow."

In addition to Mauna Loa and Kilauea, there are two other volcanoes currently erupting in the United States. Pavlof Volcano in Alaska has been venting gas and ash as high as 20,000 feet since last month and Alaska's Volcano Observatory has also reported a slow lava effusion from Great Sitkin since the end of November.

Indonesia

Indonesia's Mount Semeru erupted on Sunday spewing volcanic ash 5,000 feet into the air and forcing the evacuation of nearly 2,000 people.

"A total of 10,000 cloth masks, 10,000 medical masks and 4,000 children's masks have been distributed to reduce the impact of respiratory health risks due to volcanic ash," Indonesia's National Disaster Management Agency said in a statement.

Mount Semeru is one of eight volcanoes currently erupting in Indonesia. The others include Mounts Kerinci, Krakatau, Merapi, Lewotolok, Karangetang, Ibu and Dukono.

Mount Semeru, which is located on the island of Java, is Indonesia's highest volcano and last erupted a year ago, killing 51 people. There were no casualties in Sunday's eruption. Geologists blame monsoon rains that eroded the volcano's lava dome for causing the eruption.

Italy

In Italy, a volcano erupted on the small island of Stromboli in October. The volcano billowed ash into the air and sent streams of lava into the sea, with no major damage or casualties.

Italy's National Institute of Geophysics and Volcanology recorded a lava flow leading from the northern crater of the volcano which oozed out to the Tyrrhenian Sea through a fissure in the earth's crust known as the Sciara del Fuoco or "stream of fire."

The Stromboli volcano erupted seven times in 2022. Mount Etna, another active volcano located on the Sicilian mainland, erupted in February and May of this year.

Japan

On Saturday, Sakurajima volcano on Kyushu in Japan erupted with a spectacular show of lightning, lava and ash that spewed 6,000 feet above sea level.

The eruption of Sakurajima is one of three ongoing eruptions in Japan that include Suwanosejima last month. Aira in south Japan has emitted 700 tons of sulfur dioxide each day since Nov. 21 when the volcano exploded, sending an ash plume more than a mile into the air.

Chile

Chile's Villarrica volcano, which is the country's most active volcano, erupted Sunday with two explosions and a plume of lava shooting out of the crater.

Chile's Nevados de Chillan was also active in October after an earthquake in the area.

Russia

In Russia, the Sheveluch volcano on the Kamchatka Peninsula erupted on Nov. 20, with up to 10 explosions per hour. Sheveluch is one of Kamchatka's largest and most active volcanoes with an estimated 60 large eruptions over the past 10,000 years.

Sheveluch is one of five volcanos currently erupting in Russia, that also include Alaid, Ebeko, Chikurachki and Bezymianny.

Other volcanoes currently erupting around the world can be found in the Philippines, Solomon Islands, Costa Rica, Nicaragua, Ecuador, Tanzania, Peru, Tonga, Australia, Mexico, Guatemala and Ecuador, according to the Smithsonian Institution's Global Volcanism Program.

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Earthquake swarm under Takawangha volcano continues, Alaska

Earthquake swarm under Takawangha volcano, Alaska continues since mid-November. The Aviation Color Code remains at Yellow and the Volcano Alert Level at Advisory. The last known eruption at this volcano took place in 1550 CE (VEI unknown).

The earthquakes are generally shallow, having preliminary depths of about 3 to 11 km (2 to 7 miles) below sea level.

This activity may be due to the movement of magma beneath the volcano, the Alaska Volcano Observatory (AVO) reported on December 6.

An energetic earthquake swarm was detected under the volcano on January 23, 2017. However, the seismicity over the next 24 hours waxed and waned.

Takawangha is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.

The volcano lies across a saddle from the historically active Tanaga volcano to the west.

Geological summary
Takawangha is a youthful volcano with an ice-filled caldera on northern Tanaga Island, near the western end of the Andreanof Islands.

It lies across a saddle from the historically active Tanaga volcano to the west; older, deeply eroded volcanoes lie adjacent to the east.

The summit of the dominantly basaltic to basaltic-andesite volcano is largely ice covered, with the exception of five Holocene craters that during the last few thousand years produced explosive eruptions and lava flows that reached the lower flanks.

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Series of eruptions were registered at Anak Krakatau
A series of eruptions were registered at Anak Krakatau, a volcanic island located in the Sunda Strait between the islands of Java and Sumatra in Indonesia, on January 22 and 23, 2023. The first eruption took place at 17:41 UTC on January 23 and was followed by 8 others by 02:38 UTC on January 23.

The strongest in the series took place at 01:59 UTC on January 23, producing gray to black volcanic ash column top � 500 m (1 640 feet) above the summit (� 657 m / 2 155 feet above sea level) that drifted to the southeast. The eruption was recorded on a seismograph with a maximum amplitude of 60 mm and a duration of 143 seconds.

Other events lasted from 27 to 53 and 121 seconds, producing thick ash columns up to � 300 m (980 feet) above the summit (� 457 m / 1 500 feet above sea level).1

The Aviation Color Code remains at Orange and the Alert Level at 3 (on a scale of 1-4)

The Indonesian government has issued a recommendation for the public, visitors, tourists and climbers to avoid approaching the volcano or conducting any activities within a 5 km (3.1 miles) radius of the active crater. This is to ensure the safety of those in the surrounding areas, as volcanic eruptions can be unpredictable and potentially dangerous.

It is important to note that the Anak Krakatau has a history of frequent eruptions and should be closely monitored by the authorities and the scientific community. The public is urged to follow all official recommendations and stay informed about any updates regarding the volcano’s activity.

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Earthquake swarm under Asosan volcano, Alert Level raised, Japan

A seismic swarm started under the Asosan volcano in Japan on January 30, 2023, prompting the Japan Meteorological Agency (JMA) to raise the Volcanic Alert Level from 1 to 2.

The swarm started at about 12:20 LT and increased by 15:00 LT (06:00 UTC).

The agency is urging people to refrain from entering the danger zone and stay away from the crater.

Volcanic bombs and pyroclastic flows could affect an area of about 1 km (0.6 miles) from the Nakadake crater — one of Kyushu’s most popular tourist destinations, JMA warns.

On January 19, a gas and steam plume, rising about 300 m (984 feet) above the crater, contained 800 tonnes of sulfur dioxide (SO2) emissions.

Explosive eruption at the volcano is not ruled out and may occur suddenly.

A powerful phreatic explosion took place at Asosan’s Nakadake crater at 02:43 UTC on October 20, 2021. The eruption came one week after volcanic tremors detected under the volcano suggested hot water and magma are moving underground.

While there were no reports of injuries, the eruption produced pyroclastic flows that streamed about 1.3 km (0.8 miles) west of the crater and ejected large volcanic rocks nearly 1 km (0.62 miles) to the south.1

Ash cloud reached a height of 3.5 km (11 500 feet) above the crater.

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Increased seismic activity under Aniakchak volcano, alerts raised, Alaska

The Alaska Volcano Observatory (AVO) has raised the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY for Aniakchak volcano on February 23, 2023, following an increase in seismic activity. The last eruption at this volcano took place in 1931 (VEI 4).

The number of earthquakes beneath the volcano has risen to above-background levels and shifted to shallower depths. However, there have been no signs of unrest in other monitoring data, and there is no indication that an eruption is imminent.
Aniakchak is a stratovolcano located in the Aleutian Range, about 80 km (50 miles) southwest of King Salmon, Alaska. The volcano has been monitored by the AVO since 1989.
It had at least 40 explosive eruptions during the past 10 000 years, making it the most active volcano of the eastern Aleutian arc.
According to AVO, the background seismicity at Aniakchak has mostly been characterized by deep long-period events, occurring at a rate of about four earthquakes per month. However, from October 2022 to the present, the rate of earthquakes has been more elevated and characterized by shallower earthquakes at depths less than 9 km (5.6 miles) below sea level.

The earthquake rate has further increased since January 31, with dozens of earthquakes detected per day, including an M3.7 earthquake on February 17.

We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur. Should activity increase, we will issue further notices,” AVO volcanologists said.1

In June 2022, AVO reported that strong winds in a region northwest of Aniakchak and east of Port Heiden resuspended ash and blew it northwest on June 30. A dense cloud of possible resuspended ash near ground levels was identified in Port Heiden webcam views. The altitude of the cloud was unknown, though the report noted that resuspended ash clouds typically do not rise above 5 km (16 400 feet) above sea level. The cloud was not a result of volcanic activity, and the Aviation Color Code and the Volcano Alert Level remained at Green and Normal, respectively.2

The earliest known eruption at this volcano occurred around 6300 BCE, with a maximum Volcanic Explosivity Index (VEI) of 6. This eruption was followed by several other significant explosive eruptions, including one around 1645 BCE (VEI 6) and another around 370 BCE.

In more recent times, a confirmed eruption occurred from May 1 to June 13, 1931, with a maximum VEI of 4. This was the first and only confirmed historical eruption at Aniakchak, with ashfall reported as far as Anchorage, Alaska. An uncertain eruption was reported in 1942, but there is limited information available.

Other confirmed eruptions at Aniakchak occurred around 1540 � 100 years ago (max VEI 4), 1470 � 20 years ago, 1370 � 55 years ago, 1280 � 145 years ago, 1190 � 30 years ago, and 1120 � 80 years ago. There is uncertainty around an eruption that may have occurred around 1050 AD. Another confirmed eruption occurred around 200 � 255 years ago, with a maximum VEI of 0.

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Increased seismicity beneath Tanaga volcano, Alaska

n response to increased seismicity beneath the Tanaga volcano detected on March 6 and 7, 2023, the Alaska Volcano Observatory (AVO) raised the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory.

The earthquake activity started slowly on March 6, 2023, at around 22:30 UTC, but escalated significantly on March 7, with earthquakes occurring as frequently as 2 or 3 each minute at around 06:45 UTC. The initial locations of these earthquakes indicate that they occurred at shallow depths beneath the summit of Tanaga, with the largest earthquakes having magnitudes ranging from 2 to 3.1

This volcano is located on Tanaga Island in the Andreanof Islands, which is approximately 100 km (62 miles) west of the community of Adak and 2 025 km (1 260 miles) SW of Anchorage. The island is home to the Tanaga volcanic complex, which comprises three main volcanic edifices. Tanaga Volcano is the tallest of these, standing at 1 806 m (5 925 feet) in the center of the complex.

The last reported eruption of Tanaga occurred in 1914, and earlier eruptions were reported in 1763 – 1770, 1791, and 1829. The eruptions produced blocky lava flows and occasional ash clouds, and occurred from both the summit vent and a 1 584 m (5 197 feet) high satellite vent on the volcano’s northeast flank.

The AVO monitors Tanaga Volcano using a local seismic and infrasound network, regional infrasound and lightning detection networks, and satellite data. The volcano is also being monitored for signs of unrest and possible eruption. The AVO has advised the public to stay informed and to be prepared in case of any further developments.

In addition to Tanaga Volcano, the Tanaga volcanic complex also includes Sajaka, a 1 354 m (4 443 feet)-high compound edifice immediately west of Tanaga volcano, and Takawangha, a 1 449 m (4 754 feet)-high summit to the east.

Recent fieldwork shows that recent eruptions have occurred in Sajaka and Takawangha, and it is possible that historic eruptions attributed only to Tanaga may instead have come from these other vents. Though no historical eruptions are known from Sajaka or Takawangha, parts of Takawangha’s edifice are hydrothermally altered and may be unstable, producing localized debris avalanches.

Geological summary
Tanaga volcano, the second largest volcanic center of the central Aleutians, is the central and highest of three youthful stratovolcanoes oriented along a roughly E-W line at the NW tip of Tanaga Island.

Ridges to the east and south represent the rim of an arcuate caldera formed by the collapse of an ancestral edifice during the Pleistocene.

Most Holocene eruptions originated from the Tanaga volcano itself, which consists of two large cones, the western of which is the highest, constructed within a caldera whose 400 m (1 312 feet) high rim is prominent to the SE.

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Tanaga volcano (Aleutian Islands, USA): seismic crisis continues to evolve, alert status raised to Orange

The seismic activity continues to be elevated over the past 48 hours, a typical sign of magma pushing its way towards the surface.
If the activity will persist in the increasing trend, this would be a potential tell-tale clue for an impending eruption. The largest earthquake over the past 24 hours was measured to be M 3.9 so far.
The seismic activity is also elevated at Takawangha volcano, which is about 8 km (5 miles) east of Tanaga on Tanaga Island. If an eruption were to occur, it is uncertain at this stage if it would come either from Tanaga or Takawangha.
To conclude, the AVO observatory raised the Volcanic Alert Level to Orange.

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DR Congo’s Nyamulagira volcano shows signs of erupting

The city of Goma in the east of the Democratic Republic of Congo was on Monday on high alert after a local volcano showed signs of erupting.

Local authorities in North Kivu, including the Goma Volcanological Observatory (OVG), said that "current seismic data indicates a movement of magma at shallow depths towards the central crater of Nyamulagira”, citing the name of the local mountain.

The OVG had already announced earlier the location of what it called hybrid earthquakes in the Nyamulagira and said it feared a possible "magmatic intrusion".

"We recommend to the people of Goma to remain calm and to go about their business freely," OVG said.

However, it warned pilots to fly with caution while in the area, especially taking into account the wind direction when flying over the Virunga region.

OVG Director-General Adalbert Muhindo said that volcanic products such as ash and slag from the volcano can fall on inhabited areas in the crater.

In 2021, the Nyiragongo volcano erupted, forcing the people Goma to flee to the Rubavu region of Rwanda and other cities in the DRC.

An earthquake affected both Rwanda and the DRC after the volcano erupted.

In 1977 and 2002, North Kivu was also shaken by a volcanic eruption.

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Savo volcano monitoring intensifies amid signs of awakening, Solomon Islands

The Geology Survey Division (GSD) of the Ministry of Mines and Energy has heightened its monitoring of the Savo volcano in Central Province, following recent signs of abnormal seismic activity. While officials urge the public not to panic, they advise staying informed about further developments and following safety information and warnings.

GSD has been monitoring the seismic activity at the Savo volcano in Central Province since last week. According to a public statement released by the Division, the volcano is displaying abnormal patterns, indicating that it might be waking up.1

Despite the unusual activity, the GSD has urged the public, particularly those residing in Savo, not to panic. They should instead stay informed about further developments and follow the provided safety information and warnings. The Division is responsible for monitoring earthquakes and volcanoes in the country and will release additional information as required.

On July 28, 2022, residents on Savo in the Solomon Islands reported increased seismicity to the authorities. A GSD team and the National Disaster Management Office (NDMO) investigated the volcano two days later. They observed steam-and-gas emissions rising from an area in the crater, which might indicate an active fissure. On July 31, the GSD briefed the National Disaster Operations Committee and other authorities about the increased seismicity, leading to a preparedness response. Response actions included ongoing monitoring of the island, deployment of technical teams, and the issuance of Volcano Safety Messages to inform residents on the island and surrounding areas.2

Carlos Tatapu, Geo-Hazard Officer at the Seismological Service Division, stated that the government had been closely monitoring the volcanic activity on Savo in recent years.

In the past, the Solomon Islands have experienced the eruption of the Tinakula Volcano in Temotu province, which is one of the country’s most active volcanoes. Since last year, the government has been collaborating with the U.S. Geological Survey’s Volcanic Disaster Assistance Program (VDAP) to install monitoring equipment and train local officers on Savo Island.

The equipment has been set up in Visale, North West Guadalcanal, and Savo Island, Central Islands Province. This collaboration allows the Seismological Service Section to monitor the Savo volcano’s activity during earthquakes or volcanic eruptions.

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Increased activity at Anak Krakatau volcano, Indonesia

Indonesia’s Anak Krakatau volcano experienced an increase in activity over the past 12 hours, resulting in three intense eruptions from late March 27 to early March 28, 2023.

The first notable eruption occurred at 21:12 UTC on March 27, with an ash column height of approximately 800 m (2 625 feet) above the peak or 957 m (3 140 feet) above sea level. The gray ash column had a thick intensity and was observed moving to the northeast. This eruption was recorded on a seismograph with a maximum amplitude of 60 mm and a duration of 145 seconds.1

The second eruption took place at 00:43 UTC on March 28, producing an ash column that reached 2 000 m (6 562 feet) above the peak or 2 157 m (7 073 feet) above sea level. The black ash column, with thick intensity, also moved toward the northeast. The seismograph recorded a maximum amplitude of 65 mm and a duration of 118 seconds during this eruption.

The latest reported eruption took place at 05:21 UTC on March 28, with the ash column reaching a height of 2 500 m (8 202 feet) above the peak or 2 657 m (8 717 feet) above sea level. The black ash column, with thick intensity, was observed moving to the west. A seismograph recorded this eruption with a maximum amplitude of 74 mm and a duration of 146 seconds.