Friday, June 7, 2019

"Extinct" Kamchatcka Volcano Wakes Up

In Kamchatka, Russia, a volcano long believed to be extinct is 'waking up' according to Ivan Koulakov, a geophysicist from Russia's A.A. Trofimuk Institute of Petroleum Geology and Geophysics. According to a CNN article, the scientist states that "At any moment, an eruption can occur".

The volcano in question is Bolshaya Udina, which is located SE of Tolbachik volcano, and South of Bezymianny volcano. Bezimianny volcano, like Udina, was previously considered to be extinct, prior to a period of eruption from 1955-56. That eruption was quite similar to Mount St. Helens, with a ESE facing collapse followed by lateral blast, and culminating in a dome-building event.

Bolshaya Udina has no recorded holocene eruptions, which is typically the threshold to write off a volcano as 'extinct', however as previously noted - no volcano can truly be considered extinct without monitoring data to back this up.

Indeed, many volcanoes previously considered to be extinct have erupted in historical time, which just goes to show that 'extinct' is never truly such. Chaiten in Chile, and Nabro in Eritrea were both considered to be probably extinct, but erupted with little warning. In the case of Chaiten, it was a very large and destructive eruption. In the case of Nabro, it disrupted flight plans, and issued a long lava flow that forced evacuations of lower-flank villages.

The news about Bolshaya Udina is somewhat fortunate, in that seismicity has been detected due to its closely monitored and more active neighbors. Otherwise this may have gone unnoticed until the volcano erupted.

Udina is not currently erupting, and Ivan Koulakov stated in the CNN article that there is about a 50% chance that this volcano will erupt. There are small villages nearby, which could be impacted, but the area is very sparsely populated.

If Udina does erupt, it is very possible that this would disrupt air traffic due to ash emissions, much like the 2010 eruption of Eyjafjallajökull in Iceland affected much of Europe. But due to its remote location, the impacts would likely be limited to Alaska and the Aleutian islands.

According to the Smithsonian GVP:

"The Udina volcanic massif consists of two conical stratovolcanoes constructed along a WNW-ESE line at the south end of the Kliuchevskaya volcanic group, SE of Tolbachik volcano. The andesitic western volcano, Bolshaya Udina, has a prominent lava dome on its SW flank. The basaltic Malaya Udina rises above a low saddle at the eastern end of the complex; small lava domes also occur on its flanks. This volcano is located within the Volcanoes of Kamchatka, a UNESCO World Heritage property.

The Global Volcanism Program is not aware of any Holocene eruptions from Udina. If this volcano has had large eruptions (VEI >= 4) prior to 10,000 years ago, information might be found on the Udina page in the LaMEVE (Large Magnitude Explosive Volcanic Eruptions) database, a part of the Volcano Global Risk Identification and Analysis Project (VOGRIPA)."

Wednesday, April 17, 2019

HVO Shifts Monitoring Efforts To Mauna Loa

The Hawaiian Volcano Observatory has noted increased rates of inflation at Mauna Loa after the 2018 eruption of Kilauea. Inflation rates are still below the rates observed from 2014-2017, however increased earthquakes and ground deformation have been detected after the Kilauea eruption ended, and show a consistent trend.

The shallow magma reservoirs of Mauna Loa have undergone several periods of inflation since its last eruption in 1984, but all have paused without an eruption.

It is unknown what, if any, connection Mauna Loa and Kilauea share in terms of interactions. Kilauea's magma chamber draining may have allowed more pressure to build at Mauna Loa, or caused changes in the magmatic system. Some scientists have noted that when one volcano stops erupting, the other will begin an inflation phase, occasionally leading to eruption.

HVO scientists are looking at the current state of the volcanoes to test this theory. If Mauna Loa enters into an eruptive phase while Kilauea is dormant, this would lend more credence to the theory that the two volcanoes have an effect on each other. However there have been periods, such as the 1984 eruption of Mauna Loa, where the two have emitted lava simultaneously, but simultaneous activity is somewhat rare, and short-lived.

Currently both volcanoes are at 'Normal' levels of background activity, and no eruption from Manua Loa is imminent or predicted to occur in weeks or months. With Hawaii volcanoes though, activity seems to quickly ramp up before an eruption, so vigilance is always warranted.

You can monitor the inflation of both volcanoes on HVO's website:

For Kilauea:
https://volcanoes.usgs.gov/volcanoes/kilauea/monitoring_deformation.html

For Mauna Loa:
https://volcanoes.usgs.gov/volcanoes/mauna_loa/monitoring_deformation.html





Friday, April 5, 2019

What Is Happening Off Of Mayotte Island?

A small French territory island between Africa and Madagascar is making some big news. For several months, the volcanic island of Mayotte, in the Comoros Islands (which has not had a confirmed surface eruption since 2050 BCE) is getting very noisy. So noisy in fact that the earthquakes and seismic noise it is generating has been detected worldwide. And now, scientists say this could be the result of the largest ever underwater eruption in modern history.

Mayotte Island is a volcano, however it has had no eruptive activity in historical times. Offshore however, scientists are detecting very unusual activity, and large earthquakes (a 5.0 temblor struck today following months of other strong quakes), which have generated a 'huge rumble heard all around the world'. A 5.9 magnitude quake struck on May 15, 2018, and since then, the activity has continued. The seafloor off the coast of the island is sinking at a rate of about 0.4 inches per month as well.

This has been interpreted by geologists to mean that there is a large movement of magma, and possible offshore eruption - the largest ever recorded. Due to the depths and pressure, it is unclear whether the magma has broken through the sedimentary layer, or generated a new seamount, but given the length of the activity and amount of magma involved, it is quite possible. No underwater observations have yet occurred, so this is impossible to know at the moment.


Image from the March 12, 2019 scientific publication showing three distinct seismic crisis offshore of Mayotte.

According to the summary of a detailed study published at EarthArXiv, "We believe that the 2018 crisis is associated to an eruption, despite the fact that we do not have direct observations so far. It might be the offshore eruption with the largest volume ever documented."

As for the safety of the island of Mayotte, "If the eruption lasts one year, which is typical for volcanic eruption, the subsidence of Mayotte will exceed 0.1 m which is large but not critical for the inhabitants and infrastructures, and the total volume emitted will exceed 2 (square kilometers). Such volcanic event (sic) near the coast is the largest ever observed and it may be a major teacher for the understanding of how off-shore volcanoes work."

As of today, the activity continues with a 5.0 magnitude quake. Several other large (4.0+) quakes have occurred within the week. USGS does not have instrumentation to show the smaller quakes, but local geologists are monitoring the situation intensely. 


Google Earth capture with my volcano database and USGS plugin showing the location of the last large 5.0 earthquake.

At present, there is no danger to life or property, and the island is safe. With more instruments being deployed worldwide, and with the continuing discovery of underwater volcanoes and their activities, it is likely that we'll be detecting more and more underwater eruptions with better accuracy as time goes on.

This particular eruption however, will fascinate for a long time. 





Thursday, March 28, 2019

Iceland's Tjörnes Fracture Zone Having Massive Quake Swarm

ICELAND

The Tjörnes Fracture Zone has recently reactivated with two separate quake swarms. The first, starting sometime in the last couple of weeks, had been occurring offshore near Grimsey Island. Yesterday, another swarm began taking place near the town of Kopasker, Öxarfjordur, NE Iceland, which has now generated a very long lasting swarm of quakes. Largest quake in this swarm so far had a magnitude of 4.2.


Statement from Iceland Meteorological Office

At the time of this writing, nearly 2000 events have now been recorded, with the swarm ongoing. There has been no determination whether these are purely tectonic quakes in nature, although there has also been no mention of volcanic tremor. This is of course, Iceland though, so anything can happen, as it is part of the Atlantic rifting zone. If there was ever anywhere most likely for a new volcano to pop up, it's Iceland. 


Screen grab from Iceland Meteorological Office detailing the ongoing quake sequence

Tectonic swarms like this are not uncommon around the world. In highly volcanic areas though, they are always worth watching. This particular area does not have any Holocene (past 10,000 years) eruptive centers, although some long lava flows from distant centers are present. There is a Pliocene-Pleistocene ridge to the NW of Kopasker, which appears to have formed subglacially.

New volcanoes can form in Iceland where there were previously no obvious volcanoes. The island of Surtsey was formed to the SW of Vestmannaeyjar in 1967 in a similar fracture zone. Vestmannaeyjar itself had a new volcano, Helgafell, form in 1973 with little warning, forcing the evacuation of residents, and prompting an ambitious (and ultimately successful) effort to slow and cool advancing lava with cold ocean water, to protect the harbor.

Until new data analysis emerges however, speculation is just speculation. It is likely that the swarm will eventually end, with no volcanic activity. But you never, never, discount that possibility in a place like Iceland until the facts are in. There is a concern that if the quake continues for a long period of time, it could generate up to a 6.0 magnitude quake.


****UPDATE 3/29/2019****

Statement from Iceland Meteorological Office:

Earthquake swarm in Öxarfjordur, NE-Iceland.

 The earthquake swarm in Öxarfjordur is ongoing, about 6 km SW of the town of Kópasker. The swarm began on last Saturday 23 of March.

Eight earthquakes of magnitude 3 or higher have been measured, the largest of which measured M4.2 on March 27th. Around 2200 earthquakes have been detected since the earthquake swarm started.

Today ( March 29th ) around 350 earthquakes have been detected, the largest one M2.7 at 07:18. During the last 24 hours the intensity has decreased a lot. The swarm is still ongoing. Monitoring of the earthquakes will be followed closely during the week-end.

Wednesday, March 27, 2019

Kilauea Alert Downgraded To Lowest Since 1983

HILO, HAWAII

USGS Hawaiian Volcano Observatory has downgraded Kilauea to the lowest level (Green - background) since the start of the Pu'u'O'o eruption began in 1983. This officially marked the end of the long eruptive period of Kilauea volcano, which ended in August of 2018.

Kilauea remains an active volcano, and will certainly erupt again. It is currently in an inflation phase, where the East Rift Zone's deep magma chamber is recharging at a fairly consistent rate.

USGS HVO scientists estimate that lava will return first to the summit caldera within several years,based on the rate of magma influx to the volcanic system.

Hazards remain in the area as the caldera is still a bit unstable, and the eruptive vents of Pu'u'O'o, and the LERZ vents responsible for the Leilani Estates eruption are still quite hot, and are still releasing heat. The entire zone is still off-limits to residents without escort, and off-limits absolutely to tourists.