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Earth of fire

Actualité volcanique, Articles de fond sur étude de volcan, tectonique, récits et photos de voyage

sismologia

Publié le par Bernard Duyck
Publié dans : #volcanic activity, #Sismologia
 Klyuchevskoy - 04.26.2020 / 3:16 p.m. UTC - IVS FEB RAS KVERT 

 Klyuchevskoy - 04.26.2020 / 3:16 p.m. UTC - IVS FEB RAS KVERT 

The KVERT confirms continuous activity at the Klyuchevskoy on April 27, of Strombolian type, with a lava flow on the south-eastern flank of the volcano, the Apakhonchich chute, phreatic bursts and the slag collapse accompanying these emissions.

The plume is noted at 5,500-6,000 meters asl., extending over 424 km to the northwest of the volcano.

The aviation code remains orange.

 

Sources: KVERT & VAACTokyo

April 26, 2020, ~ Eruption/Lava Flow time lapse ~ Klyuchevskoy Volcano, Russia

Klyuchevskoy - Volcanic Ash Advisory for 27.04.2020 - Doc. VAAC Tokyo

Klyuchevskoy - Volcanic Ash Advisory for 27.04.2020 - Doc. VAAC Tokyo

During the night, from 03.51 h 26.04.2020, a seismic swarm took place in the area of ​​the Phlegraean Fields of the Solfatara-Pisciarelli, consisting of a sequence of 34 tremors of magnitude between 0.0 and 3.1 , and with hypocentres between 1 and 2 km. The earthquakes were felt in the Pozzuoli region.

The seismologists of the Vesuvius Observatory (Naples Section of the INGV), who analyzed the events, did not detect any anomalies regarding the current development of the current bradisismic crisis. It is recalled that the appearance of seismic swarms normally occurs during a period characterized by bradisismic activity, such as that underway in the Phlegrean Fields since 2005. There are elements of novelty in the progression of the current phenomenon . The geochemicals of the Vesuvius Observatory are at work to carry out surveys on the fumaroles of the Solfatara-Pisciarelli area, and report that there have been no new mouths opened.

 

Sources: INGVvulcani, INGV osservatorio Vesuviano, and Associazione Italiana di Vulcanologia (AIV)

Phlegraean fields - location of earthquakes of the last days and seismogram of 04.26.2020 - Doc. INGVvulcani and seismogram statio Solfatara south edge / radsalerno.altervista.org
Phlegraean fields - location of earthquakes of the last days and seismogram of 04.26.2020 - Doc. INGVvulcani and seismogram statio Solfatara south edge / radsalerno.altervista.org

Phlegraean fields - location of earthquakes of the last days and seismogram of 04.26.2020 - Doc. INGVvulcani and seismogram statio Solfatara south edge / radsalerno.altervista.org

A total of 18 people, including 13 guards and drivers from Virunga National Park in the Democratic Republic of the Congo were killed on Friday April 24 in an ambush by militiamen. It is the deadliest attack in recent years in this sensitive region of Upper Kivu.

We must remember the ambush of April 2014, in which Emmanuel de Merode, National Park curator, anthropologist and Belgian primatologist was seriously injured. Inaugurated in 1925, the park has since suffered repeated attacks by rebel groups, militiamen and poachers.

Virunga Volcanoes - image ESA Virunga Mountains / 2016.11.11

Virunga Volcanoes - image ESA Virunga Mountains / 2016.11.11

Respect to these rangers who protect mountain gorillas, and biodiversity, risking their lives, and condolences to the families of the victims of barbarism.

The park management declares that these tragic events will not stop the development programs carried out for the benefit of the neighboring communities, who aspire to live in an atmosphere of justice and peace.

 

Source: Virunga National Park - https://virunga.org/fr/news/updated-statement-from-virunga-national-park-on-recent-attack

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Publié le par Bernard Duyck
Publié dans : #volcanic activity, #Sismologia
 Piton de La Fournaise - 04.04.2020 / 9.47am - HD / OVPF / IRT panoramic camera

Piton de La Fournaise - 04.04.2020 / 9.47am - HD / OVPF / IRT panoramic camera

At the Piton de La Fournaise, the eruption which started on 02.04.2020 on the eastern flank of the Piton de la Fournaise, around 12:20 local time, continues. The intensity of the volcanic tremor (indicator of the intensity of the eruption) has been relatively stable over the past 12 hours.

On April 3, at 6:25 a.m., the lava front could be estimated at around 1,000 m above sea level at the top of the Grandes Pentes, and 3.8 km from the national road, according to visual feedback from the webcam of the OVPF / IPGP located in Piton Cascades.

The eruption has stabilized on the central part of the eruptive fissure. The number of fountains is reduced little by little and soon the eruption will only be active on one or two mouths. In the meantime, the projected pieces of lava fall back and build a spatter-rampart which has already grown well.

On April 3 at 10:15 p.m., the thermal anomaly noted by Mirova was VRP 2607 MW (probably due to a thinning)

Note that during the lateral magma intrusion towards the eruptive site on April 2, between 8:50 am and 12:20 pm, and following the seismic crisis (8:15 am - 8:51 am), the deformations and seismicity were extremely weak. The lateral propagation was thus done in a fairly "passive" way in an already open environment and extremely weakened by the eruptions of 2019 and the eruption of February 10-16, 2020 which took place in this sector.

Piton de La Fournaise - Spatter-rampart under construction - rb photo / ImazPress Réunion 03.04.2020

Piton de La Fournaise - Spatter-rampart under construction - rb photo / ImazPress Réunion 03.04.2020

Piton de La Fournaise - Evolution of the RSAM (indicator of the volcanic tremor and the intensity of the eruption) since 02/04/2020 at 00h UT time (04h local time) on the DSO seismological station located at the top of the volcano. (© OVPF / IPGP).

Piton de La Fournaise - Evolution of the RSAM (indicator of the volcanic tremor and the intensity of the eruption) since 02/04/2020 at 00h UT time (04h local time) on the DSO seismological station located at the top of the volcano. (© OVPF / IPGP).

The CO2 fluxes in the far field soil (Plaine des Cafres / Plaine des Palmistes sectors) fell between 28/3 and 01/4 before increasing again. This could correspond to an expulsion of superficial magma (superficial reservoir) by a rise of deeper magma.

SO2 air flows have dropped since yesterday. This drop is in agreement with the visual feedback from the eruptive site which shows weaker activity today.

The estimated surface flows, from satellite data via the HOTVOLC platform (OPGC - University of Auvergne) are greatly disturbed by the cloud cover around the Piton de la Fournaise. Estimates since the start of the eruption fluctuate between 2 and 45 m³ / s with an average around 7-10 m³ / s.

 

Source: OVPF

 

Find all the information relating to the activity of Piton de la Fournaise on the various media of the OVPF-IPGP:
- the website (http://www.ipgp.fr/fr/ovpf/actualites-ovpf),
- the Twitter account (https://twitter.com/obsfournaise?lang=fr),
- and the facebook account (https://www.facebook.com/ObsVolcanoPitonFournaise/)

Piton de La Fournaire - measurement of the SO2 mass by Sentinel-5P Tropomi on 03.04.2020: 6.15 kt - Doc. Tropomi / DLR / BIRA / ESA

Piton de La Fournaire - measurement of the SO2 mass by Sentinel-5P Tropomi on 03.04.2020: 6.15 kt - Doc. Tropomi / DLR / BIRA / ESA

Piton de La Fournaise - 03.04.2020 / 5:05 pm UT - OVPF webcam Piton de Bert

Piton de La Fournaise - 03.04.2020 / 5:05 pm UT - OVPF webcam Piton de Bert

This Friday, April 03 at 04.17 local time, an earthquake of local magnitude 2.8 located 3.2 km deep was recorded under the summit of the Chaitén volcano. The National Service of Geology and Mines has indicated that this earthquake is associated with rock fracturing and the dynamics of internal fluids (hybrid earthquake). The volcanic technical alert remains on "verde".

The last period of activity of the Chaiten occurred between May 2, 2008 and May 31, 2011 (GVP). This first historic eruption produced major explosive rhyolitic activity, numerous pyroclastic flows and lahars, and was followed by the installation of a dome complex which filled much of the caldera.

 

Sources: Sernageomin & Global Volcanism Program

The eruptive plume of the Chaitén volcano - photo Patricia Santini M / 10.05.2008

The eruptive plume of the Chaitén volcano - photo Patricia Santini M / 10.05.2008

GPS measurements, along with detailed analysis and model calculations of the available data, now testify to a new magma deposit west of the Reykjanes Peninsula under Rauðhólar and Sýrfell.

The map shows the location of the magmatic deposits which would have occurred during the year on the Reykjanes peninsula. These are preliminary results and the models are simplified, but will be updated as data is received. The map indicates when the intrusions were formed - 1. in orange: January 2020 - 2. in red: February-March 2020 - 3. in green: March-April 2020. - Doc. IMO

The map shows the location of the magmatic deposits which would have occurred during the year on the Reykjanes peninsula. These are preliminary results and the models are simplified, but will be updated as data is received. The map indicates when the intrusions were formed - 1. in orange: January 2020 - 2. in red: February-March 2020 - 3. in green: March-April 2020. - Doc. IMO

This confirms the data that was collected in collaboration with the Institute of Earth Sciences, ÍSORs, HS Energy and the Icelandic Meteorological Office after the start of activities in Thorbjörn.

"The data we have processed indicates that the magma intrusion took place from mid-February to the first week of March. This image was better explained when we received data from GPS measurements from the University, which are not directly linked to our monitoring system, which means that we have not detected them so far, "says Kristín Jónsdóttir, group director of nature conservation at the Icelandic Meteorological Office.

One model places the magmatic intrusion about 8-13 km deep, which is probably deep in the earth's crust at a depth considerably higher than the two magma deposits at Thorbjörn.

"This magma deposit under Sýrfell is the third magma deposit that we have reported on the Reykjanes peninsula since the beginning of the year. The presence of this magma insert shows that it is necessary to examine activity on the peninsula Reykjanes globally, not just local activity around Svartsengi and Reykjanes, " said Kristín Jónsdóttir. It reiterates that it is too early at this stage to draw solid conclusions and underlines the need to examine the current activity in a historical context with other known events in the Reykjanes peninsula.

Rauðhólar (icelandic Red hills) - photo Roman Z / wikipedia

Rauðhólar (icelandic Red hills) - photo Roman Z / wikipedia

Rauðhólar (the Icelandic red hills):

Remains of a group of pseudocraters in the Elliðaárhraun lava fields on the south-eastern outskirts of Reykjavik, Iceland. Rauðhólar's age is around 5200 years. Originally there were more than 80 craters, but their gravel was taken and used in construction. Most of the equipment was taken away during the Second World War for constructions such as Reykjavík Airport and road construction.

 

Source: IMO

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Publié le par Bernard Duyck
Publié dans : #volcanic activity, #Sismologia
Nevados de Chillan - 29.03.2020 / 9.44 p.m. - Webcam Sernageomin

Nevados de Chillan - 29.03.2020 / 9.44 p.m. - Webcam Sernageomin

At the Nevados de Chillan volcanic complex, explosive activity was recorded on March 29 at around 6:38 p.m. local, with a scattering of ash at low altitude in an east-southeast direction.

It continued on March 30, with grayish emissions reaching a maximum of 1,400 meters.

Volcano-tectonic earthquakes dominate at the seismicity level.

The technical alert is maintained in Amarilla

 

Sources: Sernageomi & Volcanes de Chile

Stromboli - 03.31.2020 - lava overflow in the Scira del Fuoco, at 2:35 and 4:47 respectively - SPCT / INGV OE webcam
Stromboli - 03.31.2020 - lava overflow in the Scira del Fuoco, at 2:35 and 4:47 respectively - SPCT / INGV OE webcam

Stromboli - 03.31.2020 - lava overflow in the Scira del Fuoco, at 2:35 and 4:47 respectively - SPCT / INGV OE webcam

The National Institute of Geophysics and Volcanology, Etnean Observatory, informs that the surveillance networks recorded from 23:40 hours UTC approximately on March 30, 2020, a lava overflow from the crater terrace of Stromboli; lava reached the coast line at approximately 1:50 a.m. UTC on March 31.

At the same time as volcanic phenomenology, there is a seismic signal associated with episodes of rolling incandescent blocks along the Sciara del Fuoco and small landslides that generate clouds of dust.

 

Sources : INGV OE & L.G.S.

Stromboli - lava flow in Sciara del Fuoco - 31.03.2020 / à   01h45 and  6h48  -Doc. LGS

Stromboli - lava flow in Sciara del Fuoco - 31.03.2020 / à 01h45 and 6h48 -Doc. LGS

Stromboli - sismogram 31.03.2020 between 01h and 6h45 - Doc. Seismo-acoustic network LGS

Stromboli - sismogram 31.03.2020 between 01h and 6h45 - Doc. Seismo-acoustic network LGS

Sabancaya - summary of the activity between 23 and 29 March 2020 - Doc. I.G.Peru

Sabancaya - summary of the activity between 23 and 29 March 2020 - Doc. I.G.Peru

The eruptive activity of the Sabancaya volcano remained at moderate levels between March 23 and 29, with the continuous recording of moderate explosions and the consequent emission of ash and gas. Consequently, for the following days, no significant change is expected regarding its activity.

During the aforementioned period, the IGP recorded and analyzed the occurrence of approximately 536 earthquakes of volcanic origin, associated with the circulation of fluids (magma, gas, etc.) inside the volcano and accompanied columns of gas and ash up to 3 km high above the summit of the volcano, scattered towards the western, southwest and southern sectors of Sabancaya.

In addition, 16 medium to low intensity daily explosions were recorded on average. The monitoring of the deformation of the volcanic structure records significant anomalies.

Satellite surveillance has enabled the presence of 5 thermal anomalies with values ​​between 2MW and 13 MW, associated with the presence of a surface lava body in the crater of the volcano.

The volcanic alert level in orange and it is recommended not to approach within a radius of 12 km.

 

Source: IG Peru
 

Taal - main crater - taken by drone / Phivolcs archives - Raffy Tima

Taal - main crater - taken by drone / Phivolcs archives - Raffy Tima

In Taal volcano, March 29 was marked by 93 volcanic earthquakes, associated with the fracturing of rocks, including 6 of magnitude between M1.8 and M3.4, felt in the barangays Banyaga, Bilibinwang and Subic Ilaya.

Low emissions of steam plumes are observed at the main crater and at the vents along Daang Kastila Road.

On March 30, the emissions observed reached only 50 to 100 meters in height, drifting to the southwest. THE number of volcanic earthquakes has decreased and is now only 17 events.

The alert level remains at 1 / abnormal; the prohibited zones remain around the main crater and the Daang Kastila crack.

 

Source: Phivolcs

 Reykjanes Peninsula - 30.03.2020 / 5:50 pm - location and magnitude of earthquakes - Doc.IMO
 Reykjanes Peninsula - 30.03.2020 / 5:50 pm - location and magnitude of earthquakes - Doc.IMO

 Reykjanes Peninsula - 30.03.2020 / 5:50 pm - location and magnitude of earthquakes - Doc.IMO

In Reykjanes Peninsula, activity in Grindavík remained high this week after a swarm of earthquakes that started on March 12. This is the same area as where previous earthquake swarms occurred earlier this year.

About 1,000 earthquakes have been located on the Reykjanes Peninsula. The biggest earthquake of the week was M4.2 on March 18, about 5 km NW of Gunnuhver on the Reykjanes Peninsula. The earthquake was widely felt in the southwestern part of Iceland. On March 19, an M3.5 earthquake occurred 3.5 km NW of Grindavík. An M3.0 earthquake occurred on March 20 by Kleifarvatn on the Reykjanes Peninsula, where a small swarm of earthquakes occurred on the same day.

On March 28, 2020, an earthquake swarm occurred on the Reykjanes Ridge. The largest earthquakes in this swarm had a magnitude of Mw3.5. A total of seven earthquakes occurred which were greater than the magnitude Mw3.0.

 

Source: IMO

Reykjanes ridge and peninsula - location and magnitude of the earthquakes of March 29 and 30 / 1:25 p.m. - Doc. IMO
Reykjanes ridge and peninsula - location and magnitude of the earthquakes of March 29 and 30 / 1:25 p.m. - Doc. IMO
Reykjanes ridge and peninsula - location and magnitude of the earthquakes of March 29 and 30 / 1:25 p.m. - Doc. IMO
Reykjanes ridge and peninsula - location and magnitude of the earthquakes of March 29 and 30 / 1:25 p.m. - Doc. IMO

Reykjanes ridge and peninsula - location and magnitude of the earthquakes of March 29 and 30 / 1:25 p.m. - Doc. IMO

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Publié le par Bernard Duyck
Publié dans : #volcanic activity, #Sismologia
 Popocatépetl - explosion of March 21, 2020 / 10:41 p.m. - WebcamsdeMexico

Popocatépetl - explosion of March 21, 2020 / 10:41 p.m. - WebcamsdeMexico

In Popocatépetl, in the past 24 hours, 74 exhalations have been identified thanks to the surveillance system, accompanied by volcanic gas emissions, small quantities of ash and sometimes incandescent fragments. Night glow is observed.

During the day, we see the constant emission of volcanic gases and sometimes slight amounts of ash, which are dispersed to the northwest.

The activity was a little more intense in the evening, with an explosion at 10:40 pm, and the ejection of incandescent materials on the upper slopes.

This activity remains under the Amarillo Fase 2 alert.

 

Source: Cenapred & WebcamsdeMexico.

Mayotte - Earthquake between Mayotte and Anjouan on 21..03.2020 / 9h46 loc. M 5.8 (red dot epicenter) - Doc. REVOSIMA

Mayotte - Earthquake between Mayotte and Anjouan on 21..03.2020 / 9h46 loc. M 5.8 (red dot epicenter) - Doc. REVOSIMA

A strongly felt earthquake in Mayotte in the order of M5.8 was recorded on March 21, 2020 at 06:42 UT (09:46 local time Mayotte) by the Mayotte volcanological and seismological monitoring network (REVOSIMA). The epicenter was located this time between the islands of Mayotte and Anjouan, 50 km NW of Mayotte and 30 km deep.

To illustrate the order of magnitude, it had the same intensity as the strongest earthquake felt in May 2018. It was less felt, due to the distance and its depth.

Up to now, the epicenters of earthquakes have been located east of Mayotte, and originate from two areas of magmatic flux emission.

We can notice the alignment between Comoros, the new earthquake zone, Mayotte and the earthquake zone since 2018 at the SSE of the island.

It remains to determine the exact nature of the earthquake

 

Sources: REVOSIMA, OVPF and Journal de Mayotte

Reykjanes - location and magnitude of the earthquakes at 21.03.2020 / 11:00 am - Doc. IMO
Reykjanes - location and magnitude of the earthquakes at 21.03.2020 / 11:00 am - Doc. IMO
Reykjanes - location and magnitude of the earthquakes at 21.03.2020 / 11:00 am - Doc. IMO

Reykjanes - location and magnitude of the earthquakes at 21.03.2020 / 11:00 am - Doc. IMO

In the Reykjanes Peninsula, on March 20, at 8:30 p.m., an earthquake swarm started with Krysuvik. By midnight, 60 earthquakes had been detected in the region. The biggest M3 happened at 9:21 p.m. No reports were received. Then the activity decreased.

The uncertainty phase due to the uprising in Reykjanes is still valid according to the Ministry of Civil Protection.

The latest deformation results around Mt. Thorbjorn indicate that inflation causing an uprising in the region has resumed. The uprising is slower than when it was measured in January, but seems to be in the same place. The most likely explanation for the signal is that the influx of magma has started again.

 

Source: IMO / March 21 00:18 GMT

Uplift at Yellowstone and how it does NOT mean an eruption is coming - Dr. Janine Krippner and Mike Poland.

To fill this period of confinement, and for those who master English, you can follow on YouTube a series by Dr. Janine Krippner entitled "Volcano moments", including an example above.

Interviews with volcanologists on different volcanic or seismic subjects, by following this link: https://www.youtube.com/playlist?list=PLjrF2J-wVC2OreS8nFgTgVZ5fnxymyQi3

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Publié le par Bernard Duyck
Publié dans : #volcanic activity, #Sismologia
 Yasur - emission of gas and ash on 15.03.2020 / 10.45 am - Doc. VGO

Yasur - emission of gas and ash on 15.03.2020 / 10.45 am - Doc. VGO

In Vanuatu, Yasur activity is on the rise, with explosions in progress and emission of gases and / or volcanic ash observed. Villages near the volcano are likely to be impacted by ash falls and volcanic gases in an area NNW, current direction of the winds.

The volcanic alert remains at 2; the danger to life zone remains within the limits of danger zone A, approximately within 600 meters around the cone.

 

Source: VGO

Popocatépetl - activity of the last 24 hours - Doc. Cenapred / CNPC / Seguridad

Popocatépetl - activity of the last 24 hours - Doc. Cenapred / CNPC / Seguridad

Over the past 24 hours at Popocatépetl, Cenapred has identified 125 exhalations, accompanied by gas, water vapor and little ash, as well as explosions, including two minor around 11:07 p.m. and 4:05 a.m., and a moderate, the 14.03 at 8.45 p.m. All the explosions were responsible for a plume of about 1,500 meters, dispersing to the northeast, and for ejecting incandescent materials at a medium distance from the crater.

Between these episodes, gas emissions, and slight amounts of ash are reported.

Tremor was recorded for 189 minutes.

The volcanic alert remains at Amarillo Fase 2.

 

Source: Cenapred

Shishaldin - RSAM between 14.03 and 15.03.2020 at 7:30 a.m. - Doc. AVO / UTCSSBA_BHX

Shishaldin - RSAM between 14.03 and 15.03.2020 at 7:30 a.m. - Doc. AVO / UTCSSBA_BHX

AVO raised the alert level of the Shishaldin to Watch and the aviation code to orange this March 14 at 10:31 pm, following the observation on a high resolution satellite image of lava, and of what appears to be a new cone in the summit crater.

A weak tremor is also detected.

This increase is justified by a possible continuation of the activity, with little or no warning signs, resulting in lava flows outside the crater, lahars and ash clouds at low altitude.

 

Source: AVO

Klyuchevskoy - 15.03.2020 / 7:19 am - webcam IVS FEB RAS, KVERT

Klyuchevskoy - 15.03.2020 / 7:19 am - webcam IVS FEB RAS, KVERT

Strombolian activity continues at Klyuchevskoy on March 15, with an ash explosion reaching 5,500 meters asl. The ash and gas cloud drifted 170 km towards the ENE.

The aviation code remains orange, due to possible ash explosion between 5,000 and 7,000 meters asl. anytime

 

Sources: KVERT & VAAC Tokyo

 Reykjanes peninsula - location and magnitude of earthquakes at 15.03.2020 / 08h55 - Doc. IMO
 Reykjanes peninsula - location and magnitude of earthquakes at 15.03.2020 / 08h55 - Doc. IMO
 Reykjanes peninsula - location and magnitude of earthquakes at 15.03.2020 / 08h55 - Doc. IMO

 Reykjanes peninsula - location and magnitude of earthquakes at 15.03.2020 / 08h55 - Doc. IMO

The seismic swarm that started on March 12 northeast of Grindavík on the Reykjanes Peninsula is still in progress, but the intensity of the swarm has decreased since the start.

Many minor earthquakes are still detected in the region. At the start of the swarm, an M5.2 earthquake occurred approximately 5 km NE of Grindavík. During the first day of the swarm, eight more earthquakes above M3.0 were detected. Uplift is no longer observed in the area, which is likely due to the cessation of the influx of magma. The phase of uncertainty declared by the Civil Protection is still in force.

 

At 05:55, an M3.2 earthquake was detected just north of Herðubreið. More than 100 earthquakes have been located there since yesterday. About a week ago, a hundred earthquakes were also located there. Seismic swarms are common in this area, the last time an earthquake above M3.0 was detected in a similar area in November 2019.

 

Source: IMO / Icelandic Met Office

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Publié le par Bernard Duyck
Publié dans : #volcanic activity, #Sismologia
Popocatépetl - 07.03.2020 / 07h26 - WebcamsdeMexico

Popocatépetl - 07.03.2020 / 07h26 - WebcamsdeMexico

The Cenapred informs during the last 24 hours to Popocatépetl 189 exhalations, some of these events were accompanied by gas emissions and slight amounts of ash. and three minor explosions recorded yesterday at 7:30 p.m., 9:20 p.m. and March 7 at 7:23 a.m. At the seismicity level, 215 minutes of tremor were also recorded

Since this morning and until the time of this report at 11:15 a.m., volcanic gas emissions and slight amounts of ash have been presented which are scattered towards the northeast.

Cenapred requests not to access the volcano.

The Popocatépetl volcanic alert remains at Amarillo Fase 2.

 

Source: Cenapred

Popocatépetl - summary of activity over the past 24 hours - Doc. Cenapred / CNPC / Seguridad

Popocatépetl - summary of activity over the past 24 hours - Doc. Cenapred / CNPC / Seguridad

The news of volcanic areas is rather summarized at this time by news of the developed seismicity.

In the Reykjanes Peninsula, seismic activity continues at the southwestern tip of Reykjanestá since February 15. We distinguish on March 6 at 4:55 pm an earthquake of M 3.1.
Earthquakes have greatly decreased near Thorbjorn, but the status unquestionably promulgated by the Civil Protection remains current.
IMO always advises against excursions to the Eldvörp region.

 

Source: IMO

Reykjanes peninsula - location and magnitude of earthquakes - Doc. IMO 07.03.2020 / 19h20
Reykjanes peninsula - location and magnitude of earthquakes - Doc. IMO 07.03.2020 / 19h20

Reykjanes peninsula - location and magnitude of earthquakes - Doc. IMO 07.03.2020 / 19h20

On March 7, 2020 at 8:58 p.m. (Canary time), the seismic stations of the Canaria seismic network (C7) of the Canary Volcanological Institute (INVOLCAN) recorded an earthquake of magnitude 5.5 according to the Spanish Geographic Institute and M 5.2 according to EMSC (Euro-Mediterranean seismological center) and NEIC (National Earthquake Information Center).

The epicenter of this earthquake is located in the Madeira archipelago, about 50 kilometers south of Funchal, and was very clearly felt on the islands of Madeira and Porto Santo Santo. This seismic event was felt with less intensity also in Lisbon, as well as in the islands of Tenerife and La Palma, located approximately 1,000 and 380 kilometers from the epicenter respectively.
Another shake of Ml4.3 is reported at 9:22 p.m. by the IGN.

 

Sources: InVolcan, IGN and EMSC

Madère - epicenter of the earthquake of 07.03.2020 / 20.58 Can - M5.2 (review) depth 10 km - Doc.EMSC

Madère - epicenter of the earthquake of 07.03.2020 / 20.58 Can - M5.2 (review) depth 10 km - Doc.EMSC

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Publié le par Bernard Duyck
Publié dans : #Sismologia, #Tectonics

If I tell you about the Michoacán-Guanajuato volcanic field, that doesn't mean much to you ... but if I say that it shelters the Parícutin, you can see better.

This extensive volcanic field in central Mexico, 250 km by 200 km, contains more than 400 vents. The predominant volcanic form is cinder cone, but small shield volcanoes, lava domes, maars and tuff rings, lava flows without cones are also present.

The two best representatives known are the Jorullo, which was built in the 18th century and the Parícutin, which formed in a grain field between 1943 and 1952.

Seismic swarm at Michoacán - Doc. SSN / UNAM 04.02.2020 - one click to enlarge

Seismic swarm at Michoacán - Doc. SSN / UNAM 04.02.2020 - one click to enlarge

 Seismic swarm at Michoacán - Doc. SSN / UNAM on 27.01.2020

Seismic swarm at Michoacán - Doc. SSN / UNAM on 27.01.2020

Why come back today ... because from January 5 to February 3, 2020 (in progress), the National Seismology Service (SSN) reported a seismic sequence with 1,824 earthquakes located near Uruapan, in the State of Michoacán, and more generally in the Mexican Neovolcanic Axis.

The largest earthquakes in the sequence were magnitude 4.1, one of them occurred at 2:49 a.m. on January 23, 2020, two others on February 2 at 7:47 p.m. and 10:58 p.m. respectively.

Uruapan / Michoacan - epicenter of the M3.9 earthquake / depth 12 km from 02.02.2020 / 22:48 - Doc. EMSC - EMSC

Uruapan / Michoacan - epicenter of the M3.9 earthquake / depth 12 km from 02.02.2020 / 22:48 - Doc. EMSC - EMSC

This region is characterized by intense seismic activity, related to the subduction of the Cocos plate under the North American plate. Under this part of the North American plate, the Cocos plate plunges with a very small angle almost horizontally, then after about 250 km, almost under Mexico, the diving is done abruptly.

Regional tectonics  &  Diving of the Cocos plate in 2 stages / © Perez-Campos et al., GRL 2008 - one click to enlargeRegional tectonics  &  Diving of the Cocos plate in 2 stages / © Perez-Campos et al., GRL 2008 - one click to enlarge

Regional tectonics & Diving of the Cocos plate in 2 stages / © Perez-Campos et al., GRL 2008 - one click to enlarge

For the moment, and pending the results of sampling, there is no indication of a link between earthquakes and magmatic intrusion activity.

More news is expected from Cenapred and the SSN / National Seismology Service.

 

Sources:

- National seismology service / UNAM - Special report / seismic sequence from January 5 to February 3, 2020.-  http://www.ssn.unam.mx/sismicidad/reportes-especiales/2020/SSNMX_rep_esp_20200113_secuenciaMichoacan_M39.pdf

- Global Volcanism Program - Michoacán-Guanajuato - http://volcano.si.edu/volcano.cfm?vn=341060

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Publié le par Bernard Duyck
Publié dans : #Underwater volcanism, #Sismologia

A joint study by the German Center for Geoscience Research / GFZ and the Institute for Research in Astrophysics and Planetology, entitled "Drainage of a deep magma reservoir near Mayotte inferred from seismicity and deformation", examines the seismicity associated with the seismic crisis that started in June 2018.

It highlighted magmatic movements under the seabed, before and during the eruption of this new volcano off the island of Mayotte.

More than 7,000 volcano-tectonic earthquakes and 407 earthquakes of very long period were studied with new techniques adapted to compensate the lack of instrumentalization (before the MAYOBS 1 campaign with the Marion Dufresne).

For the record : Mayotte - seismic swarms 2018-2019 - Doc. archived / BRGM

For the record : Mayotte - seismic swarms 2018-2019 - Doc. archived / BRGM

 "An earthquake goes around the world" - Doc. infogram archived on 11/11/2018

"An earthquake goes around the world" - Doc. infogram archived on 11/11/2018

For the record : MAYOBS campaign - CNRS / IPGP / IFREMER / BRGM / Univ Paris 02 to 18.05.2019

For the record : MAYOBS campaign - CNRS / IPGP / IFREMER / BRGM / Univ Paris 02 to 18.05.2019

The first earthquakes responded to the propagation of a magmatic dyke from the depths of the Moho to the surface.

From June, VLP signals, lasting 20-30 minutes and so powerful that they could be recorded a thousand kilometers away, appeared ... while the subsidence of the soil at Mayotte was measured by GNSS.

The study authors interpret this as a sign of the collapse of the large deep magma chamber, more than 3.4 km³ at about 30 km deep, following its emptying.

The eruption could not be noticed at the start, the seabed being 3 km below the surface.

Seismicity highlights the stages of the formation of the underwater volcano off Mayotte.
Sketch of the deep magma reservoir and the ascending path of magma to form a new underwater volcano. Different types of seismic and surface deformation accompany the four identified phases of agitation. Doc. CESCA ET AL. 2019, NATURE GEOSCIENCE

Sketch of the deep magma reservoir and the ascending path of magma to form a new underwater volcano. Different types of seismic and surface deformation accompany the four identified phases of agitation. Doc. CESCA ET AL. 2019, NATURE GEOSCIENCE

The earthquakes continue, even if we speak less: according to data from the RéNass / National Network for seismic monitoring, January 1 was marked by 7 earthquakes, including one of M 4.8. This January 8, an earthquake of MLv 1.8 was noted.

 

Sources:

- CNRS - Espace Presse 07.01.2020 - Volcano off Mayotte: seismicity sheds light on the stages of its formation - link

- "Drainage of a deep magma reservoir near Mayotte inferred from seismicity and deformation"
Simone Cesca, Jean Letort, Hoby N. T. Razafindrakoto, Sebastian Heimann, Eleonora Rivalta, Marius P. Isken, Mehdi Nikkhoo, Luigi Passarelli, Gesa M. Petersen, Fabrice Cotton & Torsten Dahm
Nature Geoscience, January 6, 2020

- BRGM - Volcano and earthquakes in Mayotte: monitoring of earthquake-volcanic activity - REVOSIMA - link

- RéNass / National seismic monitoring network - link

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