Overblog
Editer l'article Suivre ce blog Administration + Créer mon blog

Earth of fire

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

Publié le par Bernard Duyck
Publié dans : #volcanic activity
 Taal - emission of vapors on 25.01.2020 - phot via Mahar Lagmay / UP NOAH

 Taal - emission of vapors on 25.01.2020 - phot via Mahar Lagmay / UP NOAH

Taal activity over the past 24 hours is only characterized by low to moderate emissions of white vapor plumes 100 to 800 meters high; sulfur dioxide emissions are measured at an average of 409 tonnes per day.

This apparent calm is contradicted by seismicity: the seismic network of Taal recorded 420 volcanic earthquakes, including 11 low-frequency earthquakes ... meaning that the magmatic intrusion is still present, and a possible eruption.

Alert level 4 remains effective, as well as the order to evacuate the area of ​​14 km radius around the crater.

Taal - Watercolor with ash from the volcano by Janina Sanico - photo Facebook page of the artist

Taal - Watercolor with ash from the volcano by Janina Sanico - photo Facebook page of the artist

Inspired by the animals affected by the ashes of the eruption, a Filipino artist promoting watercolors with natural pigments, Janina Sanico, collected the ashes covering the plants in her garden, and mixed them with water and a binder. to paint scenes of this eruption.

Put on social networks, some watercolors have been sold and the profits given to help the displaced people. (ABS CBN News).

Taal - last Sentinel-1 interferogram from 17 to 23.01.2020 / Diapason Geohazards TEP via DR. S.Valkaniotis

Taal - last Sentinel-1 interferogram from 17 to 23.01.2020 / Diapason Geohazards TEP via DR. S.Valkaniotis

According to European Civil Protection and Humanitarian Aid Operations, and DROMIC news, 346,000 people were affected by the eruption on January 24, including 281,907 displaced people.

The European Commission announces € 750,000 in emergency funds to help people who have lost their homes, property and livelihoods.

 

Sources: Phivolcs, ABS CBN, and European Commission.

The map of the recent eruptions of the Fernandina volcano highlights in red the area previously affected by the lava flows produced on January 12, 2020 (red area), which cover an area of ​​approximately 3.8 km2. Map obtained thanks to InSAR coherence images (processed with ISCE, P. Espín, prepared by FJ. Vásconez).

The map of the recent eruptions of the Fernandina volcano highlights in red the area previously affected by the lava flows produced on January 12, 2020 (red area), which cover an area of ​​approximately 3.8 km2. Map obtained thanks to InSAR coherence images (processed with ISCE, P. Espín, prepared by FJ. Vásconez).

The seismic activity after the January 12, 2020 eruption in Fernandina / Galapagos Archipelago has not returned to its basic levels (pre-eruption); on the contrary, it increased, presenting sporadic earthquakes of magnitude greater than M 3.0 and small seismic swarms which have evolved over time. The strongest earthquake was recorded on January 21, 2020 with a magnitude of 4.2.

In addition, a ground deformation of about 35 cm was detected in the emission zone of the lava flows. The preliminary estimate of the lava flows emitted on January 12, 2020, located east of the volcano, indicates that they cover an area of ​​approximately 3.8 km², a value lower than the estimates of the previous circumferential eruptions (2017 and 2005) .

Ground displacement map in the line of sight (LOS) in the Fernandina Island region between January 10 and 16, 2020, showing the deformation that caused the January 12, 2020 eruption. (Treaty with ISCE, P. Espín).

Ground displacement map in the line of sight (LOS) in the Fernandina Island region between January 10 and 16, 2020, showing the deformation that caused the January 12, 2020 eruption. (Treaty with ISCE, P. Espín).

In some of the previous volcano eruptions in the Galapagos Islands (Fernandina 2009, Wolf 2015, Sierra Negra 2018), the lack of surface activity after a first eruptive pulse can be followed by a second eruptive phase, so this is not  to exclude that something similar could happen this time in Fernandina.

The processing of Sentinel-1 satellite images between January 2019 and January 2020 indicates inflation patterns with a total displacement greater than 30 cm. In addition, the analysis of the period between December 3, 2019 and January 10, 2020 (two days before the eruption) shows a distortion of 2.3 cm in the satellite line of sight (LOS). The largest deformation, deflation of approximately 35 cm (LOS), was recorded during the eruption in the lava emission zone east of the caldera. During the same period, inflation was observed on the south-southwest flank of the 21.8 cm volcano. For the same sector between January 15 and January 21, there is a deformation of 5.79 cm.

Based on historical and geological data from the Fernandina volcano eruptions, several scenarios for a possible eruption should be considered. In the case of shield-type volcanoes, such as Fernandina, eruptions are characterized as being mainly Hawaiian, with lava flows that can come from circumferential cracks (parallel to the boiler), radial (perpendicular to the boiler)) or vents inside the caldera. Historically, the eruptive activity of the Fernandina volcano has alternated between eruptions of circumferential and radial cracks (Bagnardi et al. 2013). The eruption of January 12 to 13, 2020 is circumferential, the next activity is likely to occur due to a radial crack. In addition, according to soil deformation records, it is possible that this crack is opened by the south-southwest flank of the volcano where inflation is recorded, an area where the eruptions of 1995 and 2009 occurred.

 

Source: IGEPN

Commenter cet article

Articles récents

Hébergé par Overblog