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Earth of fire

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

volcanic activity

Publié le par Bernard Duyck
Publié dans : #Sismologie, #volcanic activity
Aerial view of the southern part of Mayotte. - Alamy Stock photo via Nat Geographic

Aerial view of the southern part of Mayotte. - Alamy Stock photo via Nat Geographic

A seismic activity has affected the island of Mayotte since the beginning of May 2018. These earthquakes form a swarm with epicentres grouped at sea, 30 to 60 km east of the coast of Mayotte. The vast majority of these earthquakes are of low magnitude, but several events of moderate magnitude (at most M5.9) have been strongly felt by the population and have damaged some buildings. Since the month of July the seismic activity has decreased but a seismicity persists which certain earthquakes felt.

Location of earthquakes from May 10 to June 20, 2018. The location of earthquakes has not changed since the beginning of the crisis. © BRGM

Location of earthquakes from May 10 to June 20, 2018. The location of earthquakes has not changed since the beginning of the crisis. © BRGM

In November, the month was particularly active with two earthquakes of Magnitude> 4 felt, November 19 (M4.5) and November 27 (M5.0).

In parallel, data from the Teria network's GPS stations installed on the island of Mayotte, which are distributed by the RGP of the Institut Géographique National (IGN), indicate since July an overall displacement of about 9 cm to the east and subsidence (subsidence) of about 8 cm. Automatic and daily calculations have been set up at the OVPF (via the Gipsy software) in order to follow these deformations, as well as the source at their origin.

Thus for the month of November, the source of "depressurization" at the origin of these movements could be located about 32 km east of Mayotte and about 37 km deep.

As initially suggested by the ENS, the hypothesis of a source of deflation corresponding to the emptying of a magmatic reservoir at the level of the seismic zone seems most likely. On November 11, 2018, a long period seismic signal was recorded, and will confirm this volcanic hypothesis.

Mayotte - earthquake of 11.11.2018 - Doc. Infogram

Mayotte - earthquake of 11.11.2018 - Doc. Infogram

Seismic activity of Mayotte - Location of the source (best model resulting from a "Mogi" type of modeling) at the origin of the movements recorded in November on GPS stations of Mayotte. Modeling realized by F. Beauducel (IPGP / IRD) and OVPF-IPGP.

Seismic activity of Mayotte - Location of the source (best model resulting from a "Mogi" type of modeling) at the origin of the movements recorded in November on GPS stations of Mayotte. Modeling realized by F. Beauducel (IPGP / IRD) and OVPF-IPGP.

Mayotte - earthquake swarm, #InSAR, published crude composite. - BRGM via Matarikipax Twitter

Mayotte - earthquake swarm, #InSAR, published crude composite. - BRGM via Matarikipax Twitter

"Although the hypothetical flow is important [...], the place where the magma (extracted from the deep reservoir) is placed on the surface (or under the surface, in the crust) is currently unknown. this date would be of the order of 1.3 km3, which is very high and never observed before at sea bottom, if it is indeed an eruption ", says Pierre Briole, physicist at the ENS

The BRGM antenna in Mayotte reports in an interview with Clicanoo that "for several months, the scientific community has come together to understand the phenomenon and answer the questions that arise from it.The deployment of new instruments on land and at sea to improve the detection and localization of the observed earthquakes is under study.In parallel with this observation mission, a request for an oceanographic campaign was made to explore both the swarm zone between Mayotte and Madagascar and, more widely, the Comoros region. " The time to be expected is of the order of one to two years.

(from Clicanoo - source ref.)

 

Sources:

- OVPF - Seismic crisis in Mayotte / Monthly bulletin

- ENS Geosciences - Volcanology - link

- BRGM - Earthquake swarm in Mayotte: situation points - link

- Clicanoo - Seismic activity: in Mayotte, the volcanic hypothesis is precise - link

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Publié le par Bernard Duyck
Publié dans : #volcanic activity, #Sismologie, #Tectonique
Mayon - archive image 02.2018 / © Thierry Sluys.

Mayon - archive image 02.2018 / © Thierry Sluys.

Mayon seismometers recorded 5 volcanic earthquakes in the past 24 hours, including one in relation to an ash emission on November 30 from 9:41 am lasting one minute; the emission of the greyish plume was followed by steam and gas plumes towards the SW.

The flow of sulfur dioxide is measured at an average of 1,377 tons / day. The inflation of the southwestern sector of the volcano is still noted.

The level 2 alert remains in effect.

 

Source: Phivolcs

Merapi - the dome the 29.11.2018 / 8h18 - photo PVMBG

Merapi - the dome the 29.11.2018 / 8h18 - photo PVMBG

At Merapi, the volume of the lava dome reached 29 November 329,000 m³, for a growth rate of about 2,500 m³ per day, down slightly.

For the day of November 30, the PVMBG informs of a white degassing at about fifty meters above the summit, and a moderate seismicity.

The activity level remains at 2 / waspada.

 

Sources: BPPTKG / PVMBG
 

News from Mayon, Merapi, La Fournaise - and Tectonic Earthquake in Alaska.

The month of November 2018 will have been calm at Piton de la Fournaise, marked by a low seismicity under the summit craters and a stop of the inflation of the building. This testifies to the stopping (or at least slowing down) of the magmatic transfers from the deep zones to the more superficial zones. Moreover, the decrease in CO2 fluxes in the far-field soil since May 2018 suggests that the transfers of new magma towards the deep zones (mantle) seem to have ceased as well. Nevertheless, the trend reversal (ie an increase in CO2 fluxes in the far-field soil) observed since October 26, will be to follow in the coming weeks to determine whether a resumption of transfers of new magma to deep zones begins.

Find all the information related to the activity of Piton de la Fournaise on 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/) of the OVPF-IPGP.

The information in this document may not be used without explicit reference.

Piton de La Fournaise - the crater Dolomieu, with in the background, the ramparts of Enclos Fouqué and the Piton des Neiges - photo archive © Bernard Duyck

Piton de La Fournaise - the crater Dolomieu, with in the background, the ramparts of Enclos Fouqué and the Piton des Neiges - photo archive © Bernard Duyck

A Magnitude 7.0 earthquake occurred on November 30 at 17:29 UTC 13 km north of Anchorage, Alaska. The hypocenter is located at a depth of 40.9 km according to the USGS.

This is a place where the Pacific tectonic plate moves northwest at about 60mm / yr and enters subduction below the North American plate.

The earthquake was strong enough to cause ruptures of slopes in a restricted area because of the low relief ... the material damage is however important.

Waiting for replicas that are not going to happen, a more complete article will follow.

NB: activity of volcanoes in current regional eruption continues without changes

 

Sources:

- USGS earthquake hazards program and EMSC

- AGU - Landslide blog - D.Petley

 Alaska - epicenter of the M 7.0 earthquake on 30.11.2018 / 17h29 - Doc. EMSC

 Alaska - epicenter of the M 7.0 earthquake on 30.11.2018 / 17h29 - Doc. EMSC

Alaska -30.11.2018 - photo USGS-Josh Bierma-Hunter Sloan Sizemore
Alaska -30.11.2018 - photo USGS-Josh Bierma-Hunter Sloan Sizemore

Alaska -30.11.2018 - photo USGS-Josh Bierma-Hunter Sloan Sizemore

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Publié le par Bernard Duyck
Publié dans : #volcanic activity
Nevados of Chillan - 29.11.2018 / 13:40 local - photo via Terremoto in Talcahuano

Nevados of Chillan - 29.11.2018 / 13:40 local - photo via Terremoto in Talcahuano

An explosion marked the Nevados de Chillan complex this November 29 at 13:38 local; the plume emitted was visible from several places in the region. Satellite images from ESA show an increase in the area of ​​thermal anomalies associated with the active lava dome in the Nicanor crater.

Explosions of varying magnitude continue, and nighttime glow is observed on the webcam.

The alert level remains in Naranja, with a prohibited area of ​​3 km radius around the active crater.

 

Sources: photos Sernageomin, via volcanes of Chile and Terremoto in Talcahuano.

Nevados de Chillan - 29.11.2018 - increase in the area of ​​thermal anomalies associated with the dome - Doc. Sentinel Hub / ESA

Nevados de Chillan - 29.11.2018 - increase in the area of ​​thermal anomalies associated with the dome - Doc. Sentinel Hub / ESA

Nevados de Chillan - continuation of the activity on 29.11.2018 / 16:38 and incandescence night on the 30.11.2018 / 7:14 - webcam Sernageomin - one click to enlarge thumbnailsNevados de Chillan - continuation of the activity on 29.11.2018 / 16:38 and incandescence night on the 30.11.2018 / 7:14 - webcam Sernageomin - one click to enlarge thumbnails

Nevados de Chillan - continuation of the activity on 29.11.2018 / 16:38 and incandescence night on the 30.11.2018 / 7:14 - webcam Sernageomin - one click to enlarge thumbnails

In Guatemala, heavy rains on 28 and 29 November on the Fuego led to the descent of strong, hot lahars, accompanied by the smell of sulfur and degassing columns, towards the Seca, Santa Teresa and El Mineral barrancas. The lahars carried ash, blocks 1 to 3 meters in diameter, volcanic materials deposited during the last eruptions.

Paths to different villages have been affected: between San Pedro Yepocapa and Sangre de Cristo, between Finca Palo Verde and El Porvenir. At Sainte-Sophie Yepocapa, a vehicle that was trying to pass ford was surprised and destroyed,  fortunately without victims.

 

Source: Insivumeh special bulletin of 29.11.2018 / 13.40 and Canal 5 of Yepocapa.

Car destroyed in Saint Sophia Yepocapa by a Fuego's lahar - photos Canal 5 of Yepocapa
Car destroyed in Saint Sophia Yepocapa by a Fuego's lahar - photos Canal 5 of Yepocapa

Car destroyed in Saint Sophia Yepocapa by a Fuego's lahar - photos Canal 5 of Yepocapa

Volcanic activity on Ambae / Vanuatu is again stable according to the VMGD, which maintains the volcanic alert at level 2, together with a 2 km safety zone around the Manaro Voui Lake vent, and zones in yellow.

Ambae - during a thinning on 25.11.2018 - Sentinel-2 images nat colors image and zoom on Lake Voui. - a click to enlarge
Ambae - during a thinning on 25.11.2018 - Sentinel-2 images nat colors image and zoom on Lake Voui. - a click to enlarge

Ambae - during a thinning on 25.11.2018 - Sentinel-2 images nat colors image and zoom on Lake Voui. - a click to enlarge

It must be remembered that the eruptions resulted in two evacuations involving 11,000 people in the last 18 months.

The first evacuation took place in September 2017, followed by a partial return; In March 2018, the eruption resumed, leading to a new voluntary evacuation at first, then mandatory in late July.

A government press release said the population should not return to the island and that Ambae chiefs would be held accountable for returning members of their communities.

Ambae people should focus their efforts on building a second home on a nearby island, he said.

Government employees will not be returned to Ambae as their safety can not be guaranteed.

However, the government has confirmed that a multi-sectoral assessment of the island will take place in the next two weeks.

 

Sources: Radio NZ & Sentinel 2

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Publié le par Bernard Duyck
Publié dans : #volcanic activity
 Turrialba - 28.11.2018 / 9.30am - photo Reina Sánchez. Guardaparque via Ovsicori 

Turrialba - 28.11.2018 / 9.30am - photo Reina Sánchez. Guardaparque via Ovsicori 

The eruption continues in Turrialba, where since November 22, plumes of ash are emitted about 500 meters above the crater. The winds blowing from the northeast push the ashes towards the Central Valley.

The emissions were sustained on the morning of November 28, with frequent Lps earthquakes.

Source: Ovsicori & RSN
 

Turrialba - 28.11.2018 / at 06:00 and 07:18 - Ovsicori webcam - one click to enlargeTurrialba - 28.11.2018 / at 06:00 and 07:18 - Ovsicori webcam - one click to enlarge

Turrialba - 28.11.2018 / at 06:00 and 07:18 - Ovsicori webcam - one click to enlarge

On November 28, during the morning, Insivumeh recorded moderate block avalanches and pyroclastic flows on the north-eastern flank of Santiaguito's Caliente dome; this activity is due to the stacking of volcanic materials and its instability. The collapses generated pyroclastic flows accompanied by ash columns at 4,000 meters asl., moving over 18 km.


This activity is continuing and it is not recommended to stay near the drainages of the north-east flank.

Santiaguito - pyroclastic flow of collapse on 28.11.2018 / 07:49 - photo Alvaro Rojas - OVSAN Insivumeh

Santiaguito - pyroclastic flow of collapse on 28.11.2018 / 07:49 - photo Alvaro Rojas - OVSAN Insivumeh

The Fuego shows strong explosions accompanied by plumes loaded with ashes; the control tower at La Aurora airport reports the presence of ashes at an altitude of 9,449 m. asl. traveling 25 km to a sector south and west this 28 November.

During the night and the morning, incandescence is observed, and projections 200 meters above the crater feed avalanches in the contours of the latter, some of which are wider in the direction of the main barrancas.

 

Sources: Insivumeh & Conred

Fuego - important emission of ashes on 28.11.2018 - photo Volcanofiles

Fuego - important emission of ashes on 28.11.2018 - photo Volcanofiles

At Etna, strombolian explosions continue at the new south-east crater, and feed the lava flow that moves towards Valle del Bove. Explosions are more frequent, and almost continuous at times.

Continuous intra-crateric activity at the northeast crater and Bocca Nuova, with nocturnal incandescence revealing it.

All this activity remains confined to the summit craters, without threat to the populations around the volcano, nor production of ashes.

Sources: Boris Behncke and Gio Giusa

Etna - Strombolian activity and lava flow towards the Valle del Bove - photo 29.11.2018 Gio Giusa

Etna - Strombolian activity and lava flow towards the Valle del Bove - photo 29.11.2018 Gio Giusa

Etna the 29.11.2018 at dawn - the activity of the NSEC blackens the white coat covering the peaks - photo Boris Behncke

Etna the 29.11.2018 at dawn - the activity of the NSEC blackens the white coat covering the peaks - photo Boris Behncke

In Kadovar, Papua New Guinea, the central vent is still active, with a plume loaded with ashes.

A Sentinel 2 image shows several incandescent fires at the top of the island-volcano.

Sources: Local Observers and Sentinel 2

Kadovar - incandescence in several points at the top - zoom in a picture Sentinel 2 SWIR from 26.11.2018 - one click to enlarge

Kadovar - incandescence in several points at the top - zoom in a picture Sentinel 2 SWIR from 26.11.2018 - one click to enlarge

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Publié le par Bernard Duyck
Publié dans : #volcanic activity
Merapi - 27.11.2018 - Increasing degassing - photo T. Harjanto. / Jakarta Post

Merapi - 27.11.2018 - Increasing degassing - photo T. Harjanto. / Jakarta Post

 Top dome of Merapi - photo BPPTKG 23.11.2018

Top dome of Merapi - photo BPPTKG 23.11.2018

The head of the CVGHM recalled in an interview with the Jakarta Post that the safety distance for the Merapi is 3 km, to be respected since the dome in continuous growth can collapse by generating pyroclastic flows.

This kind of event brought to light the 300-meter incandescent avalanche that occurred around 7:05 pm on November 23, considered by the authorities as non-dangerous.

On the other hand, Agus Budi Santoso, head of BPPTKG, mentioned the possibility of pyroclastic flows if the extrusion of lava increases.

The tension is busy climbing ... to follow!

 

Sources: Jakarta Post / BPPTKG.

Merapi - Incandescent avalanche on November 23rd / 7pm - Doc. BPPTKG

Merapi - Incandescent avalanche on November 23rd / 7pm - Doc. BPPTKG

At Mayon, the analysis of seismicity reveals four volcanic earthquakes, two of which related to a phreatic eruption on November 26 at 7:59 and 8:04 am.

On November 27, another phreatic eruption was observed at 5:33 am, generating a greyish ash plume rising 500 meters above the summit, followed throughout the day by vapor emissions to a western sector.

Nighttime glow is observed; the flow of sulfur dioxide is measured at an average of 1.996 tonnes / day on 27.11.

The level 2 alert is maintained.

 

Source: Phivolcs.

The Mayon dominating the agglomeration of Legazpi - Luzon island photo

The Mayon dominating the agglomeration of Legazpi - Luzon island photo

Since November 24, the Karangetang has thermal anomalies qualified by Mirova of light to moderate, between 3 and 16MW.

These anomalies correspond to an increase in seismicity since the same date, in relation with magma movements and degassing.

Emissions have increased at the northern crater, where the Sentinel 2 satellite has detected a thermal signal since 26 September.

The photos of the last days reveal a plume consisting of the northern crater and degassing at the south crater.

Karangetang - seismicity and thermal anomalies on 27.11.2018 - doc.Magma Indonesia and Mirova Modis - one click to enlarge 
Karangetang - seismicity and thermal anomalies on 27.11.2018 - doc.Magma Indonesia and Mirova Modis - one click to enlarge 

Karangetang - seismicity and thermal anomalies on 27.11.2018 - doc.Magma Indonesia and Mirova Modis - one click to enlarge 

Karangetang - image Sentinel-2 image nat colors 4,3,2 from 26.09.2018 - - one click to enlarge

Karangetang - image Sentinel-2 image nat colors 4,3,2 from 26.09.2018 - - one click to enlarge

Karangetang - activity from 26.11.2018 / 7h03 & 7h52 / Magma Indonesia and from 27.11.2018 / Tris Tawera Bawole via Facebook - one click to enlarge .Karangetang - activity from 26.11.2018 / 7h03 & 7h52 / Magma Indonesia and from 27.11.2018 / Tris Tawera Bawole via Facebook - one click to enlarge .
Karangetang - activity from 26.11.2018 / 7h03 & 7h52 / Magma Indonesia and from 27.11.2018 / Tris Tawera Bawole via Facebook - one click to enlarge .

Karangetang - activity from 26.11.2018 / 7h03 & 7h52 / Magma Indonesia and from 27.11.2018 / Tris Tawera Bawole via Facebook - one click to enlarge .

Karangetang - higher thermal signal at north crater than south crater - image Sentinel-2 image SWIR 25.11.2018 -  one click to enlarge

Karangetang - higher thermal signal at north crater than south crater - image Sentinel-2 image SWIR 25.11.2018 - one click to enlarge

Note that the Karangetang is a stratovolcano that houses four north-south aligned summit craters, and is one of the most active Indonesian volcanoes, with more than 40 major eruptions recorded since 1675, and many more undocumented. The eruptions of the 20th century include a frequently explosive activity, which is accompanied by pyroclastic flows and lahars, and presence of domes in the summit craters.

Sources: Magma Indonesia, Sentinel2 and Mirova - Global Volcanism Program

Popocatépetl - summary of earthquakes VT of November 2018 - Doc. Oscar Zepeda / Cenapred - 28.11.2018

Popocatépetl - summary of earthquakes VT of November 2018 - Doc. Oscar Zepeda / Cenapred - 28.11.2018

The seismic activity of Popocatépetl is marked this 27 November by four volcano-tectonic earthquakes of magnitude between 1.4 and 1.9, respectively at 17h24, 17h31 with two earthquakes close together, and 22h35.

Oscar Zepeda, director of analysis and risk management at Cenapred, reports that during the month of November, 56 volcano-tectonic earthquakes were recorded, and the month is not over.

Source: Cenapred

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Publié le par Bernard Duyck
Publié dans : #volcanic activity
Fuego - 26.11.2018 - photo Edilverto Santos via Clima Guatemala

Fuego - 26.11.2018 - photo Edilverto Santos via Clima Guatemala

The Fuego maintains moderate to strong explosions at a rate of 12 to 15 per hour, a vulcanian-type activity according to Insivumeh.

It is accompanied by eruptive columns laden with ashes rising to 5,000 meters asl. and shock waves and vibrations felt within a radius of 25 km.

A change of wind direction, November 26 in the morning from south to north, brings the ashes to Alotenango, San Miguel, Dueñas, Antigua Guatemala and Ciudad Guatemala, the capital.

2018.11.26 10:45 Fuego - Doc.Insivumeh


Sources: Insivumeh & Conred.

Fuego - 26.11.2018 - photo Jiuwit Rosas via William Chigna / Twitter

Fuego - 26.11.2018 - photo Jiuwit Rosas via William Chigna / Twitter

At Karangetang, located north of Siau Island, itself north of Sulawesi, moderate thermal anomalies have been reported since 24 November.

The VAAC Darwin issued an ash dispersion advisory on November 25, and Magma Indonesia reported a small eruption on November 25 and 26, 2018. The height of the emitted ash plume could not be observed due to cloud cover, and has been estimated at 2.284 meters asl .

The activity level is set at 2 / waspada, associated with a danger zone of 1.5 km around the crater, extended to 2.5 km SE, S, SW and O, and an orange VONA.

 

Sources: Magma Indonesia.

Karangetang - thermal anomalies on 27.11.2018 / Mirova and seismicity on 26.11.2018 / Magma Indonesia - one click to enlargeKarangetang - thermal anomalies on 27.11.2018 / Mirova and seismicity on 26.11.2018 / Magma Indonesia - one click to enlarge

Karangetang - thermal anomalies on 27.11.2018 / Mirova and seismicity on 26.11.2018 / Magma Indonesia - one click to enlarge

Karangetang - 25.11.2018 / 7:52 AM WITA - photo Magma Indonesia

Karangetang - 25.11.2018 / 7:52 AM WITA - photo Magma Indonesia

Karangetang - 26.11.2018 / 7.30am WITA - photo Magma Indonesia

Karangetang - 26.11.2018 / 7.30am WITA - photo Magma Indonesia

At Etna, a lava flow, emitted by the "Puttusiddu" vent on the east flank of the new south-east crater, came out of the pit crater on November 26th. His diet continues on November 27 in the morning.

Sources: Boris Behncke and Benito Morabito.

Etna - 26.11.2018 after midnight - On the left, the flow of the puttusiddu / NSEC and on the right, the incandescence at the level of the Bocca Nuova - picture Boris Behncke

Etna - 26.11.2018 after midnight - On the left, the flow of the puttusiddu / NSEC and on the right, the incandescence at the level of the Bocca Nuova - picture Boris Behncke

On Deception island, in the South Antarctic Shetland Islands, the eruption that formed the huge central caldera, with a current diameter of 8-10 km, has only been accurately dated, based on analysis. lacustrine and marine sediments, and ice cores.

The study reveals conclusive and multidisciplinary evidence of a major volcanic episode, with far-reaching effects, 3,980 years ago, accompanied by a volcano-climatic impact on a hemisphere.

Source:The timing and widespread effects of the vast Holocene volcanic eruption in Antarctica - by Dermot Antoniades & al - Scientific Reports volume 8, Article number: 17279 (2018)

Above :Location map showing (A) Deception Island, Byers Peninsula and the Antarctic Peninsula; and (B) sites across Antarctica where the Deception Island caldera collapse event is recorded by tephra and/or rapid post-seismic sediment deposition in ice, lake and marine sediment cores.   Under : (A) Map of Deception Island showing the general geology and outcrop locations of the Outer Coast Tuff Formation (OCTF) (modified from ref.10)  (B) Image of the Vapour Col succession illustrating the contact between the OCTF and post-caldera deposits; (C) Detail of OCTF deposits on Deception Island; (D) detail of Tephra T3 from Byers Peninsula (Lake Limnopolar, core LIM08_F2B), with alternating organic and mineral sedimentation below T3 and rapid, massive sediment above; note the coarseness of the tephra Doc. The timing and widespread effects of the largest Holocene volcanic eruption in Antarctica
Above :Location map showing (A) Deception Island, Byers Peninsula and the Antarctic Peninsula; and (B) sites across Antarctica where the Deception Island caldera collapse event is recorded by tephra and/or rapid post-seismic sediment deposition in ice, lake and marine sediment cores.   Under : (A) Map of Deception Island showing the general geology and outcrop locations of the Outer Coast Tuff Formation (OCTF) (modified from ref.10)  (B) Image of the Vapour Col succession illustrating the contact between the OCTF and post-caldera deposits; (C) Detail of OCTF deposits on Deception Island; (D) detail of Tephra T3 from Byers Peninsula (Lake Limnopolar, core LIM08_F2B), with alternating organic and mineral sedimentation below T3 and rapid, massive sediment above; note the coarseness of the tephra Doc. The timing and widespread effects of the largest Holocene volcanic eruption in Antarctica

Above :Location map showing (A) Deception Island, Byers Peninsula and the Antarctic Peninsula; and (B) sites across Antarctica where the Deception Island caldera collapse event is recorded by tephra and/or rapid post-seismic sediment deposition in ice, lake and marine sediment cores. Under : (A) Map of Deception Island showing the general geology and outcrop locations of the Outer Coast Tuff Formation (OCTF) (modified from ref.10) (B) Image of the Vapour Col succession illustrating the contact between the OCTF and post-caldera deposits; (C) Detail of OCTF deposits on Deception Island; (D) detail of Tephra T3 from Byers Peninsula (Lake Limnopolar, core LIM08_F2B), with alternating organic and mineral sedimentation below T3 and rapid, massive sediment above; note the coarseness of the tephra Doc. The timing and widespread effects of the largest Holocene volcanic eruption in Antarctica

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 Mayon / Philippines - 26.11.2018 / 8:23 - Stock Photo Phivolcs Dost

Mayon / Philippines - 26.11.2018 / 8:23 - Stock Photo Phivolcs Dost

Two phreatic eruptions were observed at Mayon on November 26, respectively at 7:59 and 8:05; they were accompanied by a plume of gray to gray-white ash rising between 300 and 500 meters above the summit. The sulfur dioxide flux was measured at an average of 1,943 tonnes / day on 25 November.

The building is in inflation of its south-east sector, measured between October 22nd and 31st, 2018, while a sector north is deflating it, following a magmatic intrusion deep in the volcano.

The Phivolcs reminds not to enter the zones of permanent danger of 6 to 7 km according to the sectors. The alert level remains at 2.

 

Source: Phivocs-Dost.

Turrialba - 24.11.2018 / 14:38 - webcam Ovsicori

Turrialba - 24.11.2018 / 14:38 - webcam Ovsicori

 Turrialba - superb wide shot of Federico Chavarría-Kopper via Ovsicori, 24.11.2018, revealing from left to right, the way up to the viewpoint, the active crater and the lakes of the summit.

Turrialba - superb wide shot of Federico Chavarría-Kopper via Ovsicori, 24.11.2018, revealing from left to right, the way up to the viewpoint, the active crater and the lakes of the summit.

In Turrialba, an eruption has continued since 23 November; a column of ash frequently rises 200 meters above the crater.

Seismicity is characterized by earthquakes LP of middle amplitude and tremor. Strong infrasonic signals have been recorded for 2 days.

Strombolian eruptions occurred in the night of November 23-24, with ejection of gas and ash, and bombs falling in an eastern sector in the vicinity of the crater.

Costa Rica Central Valley - Spatial distribution of earthquakes - 1: Coronado; 2: Cartago; 3: Escazú; 4: South of Cartago - Doc .Ovsicori

Costa Rica Central Valley - Spatial distribution of earthquakes - 1: Coronado; 2: Cartago; 3: Escazú; 4: South of Cartago - Doc .Ovsicori

Together, the Central Valley was marked this week by intense seismic activity, in four locations: Coronado, Cartago, south of Cartago and Escazú.

The earthquakes were felt by the population because of their shallow depth (less than 10 km), but they remain in the domain of the norm in this region with complex tectonics, crossed by many active faults.

Sources: Ovsicori & RSN

ErtaAle - 25.11.2018 / 22:45 - thermal anomalies - Doc.Mirova MODIS_Latest10NTI

ErtaAle - 25.11.2018 / 22:45 - thermal anomalies - Doc.Mirova MODIS_Latest10NTI

In Ethiopia, news of Erta Ale is scarce.

The images provided by the Sentinel 2 satellite and the data from the Mirova site show a strong degassing at the intracalderic lava lake (masking the incandescence ?) and a thermal anomaly reaching these days 239 MW in the lava field located 15 km further east.

 

Sources: Sentinel 2 & Mirova Modis.

Erta Ale - 25.11.2018 - degassing of the intracrateric lava lake and incandescence in the eastern field - image Sentinel 2 SWIR - one click to enlarge

Erta Ale - 25.11.2018 - degassing of the intracrateric lava lake and incandescence in the eastern field - image Sentinel 2 SWIR - one click to enlarge

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Fuego - moderate avalanche on 23.11.2018 - photo Franklin Reyes, Finca La Candelaria. via Conred

Fuego - moderate avalanche on 23.11.2018 - photo Franklin Reyes, Finca La Candelaria. via Conred

The Fuego shows a slight increase in activity, with explosions accompanied by an ash plume rising to 4,700-5,000 meters asl. traveling 20 km towards a western sector.

Incandescence is observed, as are weak avalanches around the crater; some projectiles reach the limit of the vegetation, in the direction of the barrancas Las Lajas, Ceniza and Seca; ashfall is reported on San Pedro Yepocapa, Panimache, El Porvenir, Morelia, Santa Sofia, Sangre de Cristo and Finca Palo Verde.

Early in the morning of November 14, stronger explosions generating significant fallout are recorded.

Sources: Insivumeh & Conred

Fuego - strong explosions early in the day on 24.11.2018 - Insivumeh seismogram

Fuego - strong explosions early in the day on 24.11.2018 - Insivumeh seismogram

Fuego - night activity (no better photo at the moment) - photo 24.11.2018 / report of 5:42 / Insivumeh

Fuego - night activity (no better photo at the moment) - photo 24.11.2018 / report of 5:42 / Insivumeh

At the Nevados de Chillan complex, whitish pulsatile emissions, dominated by water vapor, mark the crater Nicanor.

Sernageomin provides nighttime glow, small explosions and ballistic projections.

This activity remains in the standards of the technical alert Naranja, in connection with the cycles of growth and destruction of the dome nestled in the crater.

Source: Sernageomin

The Nevados de Chillan complex - Photo Sernageomin

The Nevados de Chillan complex - Photo Sernageomin

The volume of the Merapi summit lava dome was 218,000 m³ on 21 November 2018, with a growth rate of 2,600 m³ / day, a little higher than the previous week.

The seismic activity is lower than last week.

On visual and instrumental results, the lava dome is considered stable.

The activity level remains the same: 2 / waspada

Sources: PVMBG & BPPTKG

Merapi - top and dome 22.11.2018 - Doc BPPPTKG
Merapi - top and dome 22.11.2018 - Doc BPPPTKG

Merapi - top and dome 22.11.2018 - Doc BPPPTKG

Merapi - evolution of the dome between 15.11 and 21.11.2018 - Doc.PVMBG

Merapi - evolution of the dome between 15.11 and 21.11.2018 - Doc.PVMBG

The JMA has raised the alert level of Meakandake to 2 / do not approach the crater, on November 23 at 12:30 JST, following an increase in superficial volcanic earthquakes near the crater Ponmachineshiri since 20 November. (271 on 22.11, 557 on 23.1 at 3 pm local time)

However, there is no reported deformation or plume emitted.

 Meakandake - alert reported at 2 on 23.11.2018 / 12.30 pm JST - Doc.JMA

Meakandake - alert reported at 2 on 23.11.2018 / 12.30 pm JST - Doc.JMA

Akan caldera - Meakan-dake on the left, Akan Fuji in the center -  JMA photo

Akan caldera - Meakan-dake on the left, Akan Fuji in the center - JMA photo

Within the Akan volcanic complex, characterized by a 13 km by 24 caldera, only the Meakandake group has been historically active; the last activity dates back to November 2008, with a small phreatic eruption.

Sources: JMA, NHK web news, and Gloval Volcanism Program / Akan

Last activity of the Meakandake - steam emissions on 28.11.2008 from both the 96-1 crater  and the number 4 crater. - JMA  in GVP

Last activity of the Meakandake - steam emissions on 28.11.2008 from both the 96-1 crater and the number 4 crater. - JMA in GVP

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Publié le par Bernard Duyck
Publié dans : #volcanic activity
Popocatépetl - dome # 80 during an overview of Cenapred / Semar teams - photo 22.11.2018

Popocatépetl - dome # 80 during an overview of Cenapred / Semar teams - photo 22.11.2018

An overflight of the Popocatépetl, carried out with the support of the Marine Secretariat / SEMAR allowed the observation of the new dome # 80 of the volcano: 250 meters in diameter, and a thickness of 30 meters, its volume reaches 1.5 million of m³.

During the last 24 hours, 46 exhalations of water vapor, gas, and a small amount of ash are recorded.

The volcanic alert remains at Amarillo Fase 2, accompanied by a 12 km safety zone.

Source: Cenapred

Popocatépetl - dome # 80 during an overview of Cenapred / Semar teams - photo 22.11.2018
Popocatépetl - dome # 80 during an overview of Cenapred / Semar teams - photo 22.11.2018

Popocatépetl - dome # 80 during an overview of Cenapred / Semar teams - photo 22.11.2018

In Fuego, constant explosions accompanied by expulsions of a dark gray plume continue.

The avalanches of blocks and ashes, accumulated during the eruption of November 18, continue in the Seca, Ceniza, El Jute, Las Lajas and Honda barracks.

This activity can continue in the coming days, it is recommended not to park in the main drainages.

Sources: Insivumeh and Conred

Fuego - avalanches on 22.11.2018 in the main drainages - photo Conred

Fuego - avalanches on 22.11.2018 in the main drainages - photo Conred

Fuego - une des explosions le 22.11.2018 - photo Insivumeh

Fuego - une des explosions le 22.11.2018 - photo Insivumeh

Three craters are still active this November 22 at the top of Mount Etna: a Strombolian activity animates the Bocca Nuova, and the "puttusiddu" of the new crater southeast. The crater northeast is also continuing its activity.

Source: Boris Behncke

Etna - 22.11.2018 / 21h13 - Activity of the Bocca Nuova on the left, and the "puttusiddu" of the NSEC on the right - the NE crater is not visible in the photo - photo Boris Behncke

Etna - 22.11.2018 / 21h13 - Activity of the Bocca Nuova on the left, and the "puttusiddu" of the NSEC on the right - the NE crater is not visible in the photo - photo Boris Behncke

Etna - 22.11.2018 / 20h59 - webcam LAVE Schiena del Asino

Etna - 22.11.2018 / 20h59 - webcam LAVE Schiena del Asino

At Kilauea, colder and wetter conditions result in the formation of a small amount of H2S, in addition to SO2.

H2S is most commonly detected during interruptions of the trade winds and at the downwind locations of Kīlauea Peak, Pu'u'Ō'ō, and the 2018 Crack System of the Lower East Rift Zone.

 Kilauea top - odorous outgassing  on 21.11.2018 - photo Big Islsnd video news

Kilauea top - odorous outgassing  on 21.11.2018 - photo Big Islsnd video news

Pu'u 'O'o - 20.11.2018 / 6h30 - intense degassing - extreme exposure photo

Pu'u 'O'o - 20.11.2018 / 6h30 - intense degassing - extreme exposure photo

The rotten egg odor of H2S is seen at lower concentrations ranging from 0.0005 to 0.3 ppm. The state of Hawaii has defined a "nuisance level" for H2S at 0.025 ppm, based on the odor threshold. Negative symptoms of H2S exposure occur only when the concentrations are well above the olfactory threshold.

According to Occupational Safety and Health Administration (OSHA) prolonged exposure to 2-5 ppm may cause headaches, eye irritation, nausea, or breathing problems in some asthmatics (https: //www.osha. gov / SLTC / hydrogensulfide / hazards, html). Concentrations measured in populated areas around Kīlauea are less than 1 ppm.

Although humans can detect H2S at very low concentrations, their sense of smell does not perceive it at high concentrations.

 

The situation is temporary, since during the next chapter of Kīlauea volcano activity, when the magma will rise to the surface, we can expect a decrease in H2S emissions and a return to the more familiar smell of SO2 and particulate dominated vog.

Source: Big Island video news

Kilauea East rift zone - 20.11.2018 / 6.30 am - fissure 8 degassing  - photo Extreme exposure

Kilauea East rift zone - 20.11.2018 / 6.30 am - fissure 8 degassing - photo Extreme exposure

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Publié le par Bernard Duyck
Publié dans : #volcanic activity
 Veniaminof - 21.11.2018 / 9:59 - photo Janet Schaefer / AVO

Veniaminof - 21.11.2018 / 9:59 - photo Janet Schaefer / AVO

Veniaminof - 21.11.2018 / 12:16 AKST - Perryville camera - via Schaefer, Janet / AVO

Veniaminof - 21.11.2018 / 12:16 AKST - Perryville camera - via Schaefer, Janet / AVO

 Veniaminof - 21.11.2018 / 11:49 - the plume is about 200 km at the time of the shooting - Terra-1 Modis satellite via AVO

Veniaminof - 21.11.2018 / 11:49 - the plume is about 200 km at the time of the shooting - Terra-1 Modis satellite via AVO

During the night of 19 to 20 November, ash emissions increased significantly at Veniaminof : the plume exceeded 4,500 meters before spreading to the southeast. The situation justified the passage of the volcanic warning level to Warning and the aviation code to Red.

The emissions continued during the day, to extend over 400 km until about 14:45 AKST.

A short eruptive pulse followed, visible on the Peryville webcam at 15:26 AKST, and largely dissipated at 17:26 AKST.

Emissions of ashes were no longer visualized afterwards.

Veniaminof - RSAM from 15 to 22.11.2018 - Doc.AVO


The seismic activity continues as a continuous tremor, and ash emissions are likely to resume at any time.

Veniaminof - tephra under an electron microscope - Doc.AVO

Veniaminof - tephra under an electron microscope - Doc.AVO

An electron microscopic analysis of tephra, collected on October 26, shows grains composed of a vitreous matrix of andesite with abundant microlites of olivine, plagioclase and clinopyroxene.

Source: AVO & Planetlabs

Fuego - small explosion 21.11.2018 / 20h21 - photo William Chigna

Fuego - small explosion 21.11.2018 / 20h21 - photo William Chigna

In Fuego, after the official shutdown of the 5th eruption of the year, the activity is marked by weak to moderate explosions, accompanied by ash plumes at 4,500-4,600 meters asl, traveling 12 km to the west and southwest. Nighttime glow is observed.

Fuego - 21.11.2018 - avalanche of volcanic materials in the barranca Las Lajas. - photo Conred

Fuego - 21.11.2018 - avalanche of volcanic materials in the barranca Las Lajas. - photo Conred

Due to the existing instability in the different drainages, strong avalanches occurred in the Seca, Ceniza, El Jute, Las Lajas and Honda barrancas; blocks of 2 to 3 meters and fine particles were mobilized in a south-southwest direction.

Small pyroclastic flows are reported by Rüdiger Escobar Wolf, the largest at 16h15 UTC (camera station FH12 / see video)

This situation can happen again in the hours and days to follow.

Source: Insivumeh

Video de los flujos piroclasticos esta mañana tomado de las imagenes de la camara de vigilancia de @insivumehgt en la estacion FG12. Los flujos mas grandes empezaron aprox a las 16:15 UTC segun el reloj de la camara...

At Etna, Strombolian explosions follow the small lava flow reported yesterday at "puttusiddu", the lateral crater of the new southeastern crater (NSEC).

The activity generates a rain of lapilli falling in the inner part, which fills gradually following the various eruptions. A new small flow is observed this November 22, the first hour, inside the pit crater.

Source: Benito Morabito / Osservatorio DIRECT CIELO and Salvatore Lo Giudice

 Etna NSEC - strombolian activity from 21.11.2018 / 20h05 - photo Salvatore Lo Giudice

Etna NSEC - strombolian activity from 21.11.2018 / 20h05 - photo Salvatore Lo Giudice

Etna NSEC - small lava flow in the crater "puttusiddu" - photo 22.11.2018 / 0h58 - photo via Benito Morabito / Osservatorio DIRETTA CIELO

Etna NSEC - small lava flow in the crater "puttusiddu" - photo 22.11.2018 / 0h58 - photo via Benito Morabito / Osservatorio DIRETTA CIELO

A smell of sulfur is reported around Sólheimajökull and Jökulsá á  Sólheimasandur. The windy conditions expected over the next few days may allow gases to accumulate in low-lying areas at dangerous concentrations.

No change in hydrological, gaseous, or seismic data.

It is recommended not to stay close to the Jökulsá river in Sólheimasandur.

Source: IMO

Sólheimajökull is one of the glaciers-emissaries south of Myrdalsjökull, which recovers Katla volcano

Sólheimajökull is one of the glaciers-emissaries south of Myrdalsjökull, which recovers Katla volcano

Sólheimasandur under a typical Icelandic sky - photo © Bernard Duyck

Sólheimasandur under a typical Icelandic sky - photo © Bernard Duyck

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