May 07 , 2020. EN. Italy : Stromboli , Colombia : Nevado del Ruiz , Solomon Islands : Kavachi , El Salvador : San Miguel (Chaparrastique) , Chile : Nevados of Chillan .

May 07 , 2020.



Italy , Stromboli :

Weekly bulletin from April 27, 2020 to May 03, 2020 (issue date 05/05/2020)


In light of the monitoring data, it is highlighted:
1) VOLCANOLOGICAL OBSERVATIONS: During this period, normal explosive activity of the strombolian type was observed accompanied by degassing and splashing activities. The hourly frequency of explosions fluctuated between average values ​​(15 events / h on April 30) and high values ​​(21 events / h on April 28). The intensity of the explosions was mainly low in the area of ​​the North crater and medium in the area of ​​the Center-South crater.
2) SEISMOLOGY: The seismological parameters do not show significant variations.
4) DEFORMATIONS: Data from the Stromboli soil deformation monitoring networks did not show any significant changes last week.
5) GEOCHEMISTRY: The flow of SO2 is at an average level. The last measurement of the CO2 / SO2 ratio is at an average value (last update on 02/09/2020). The isotopic ratio of helium remains on average values ​​(last update of 09/03/2020). There is no update on the CO2 released by the soil.
6) SATELLITE OBSERVATIONS: The thermal activity in the summit area is low.

The analysis of the images recorded by the cameras placed at an altitude of 400m, at an altitude of 190m and at Punta dei Corvi made it possible to characterize the eruptive activity of Stromboli. During the reporting period, the explosive activity was mainly produced by at least 4 (four) eruptive vents located in the area of the North crater and by at least 2 (two) eruptive vents located in the area of the Center-South crater . All the vents are located inside the depression which occupies the crater terrace.
Due to unfavorable weather conditions on April 29, May 01 and May 03, the visibility of the crater terrace was insufficient for a correct description of the eruptive activity.

In the North zone, the explosions were mainly of variable intensity, low (less than 80 m in height) to medium (less than 150 m in height) emitting coarse materials (lapilli and bombs). During certain explosions, abundant fallout products covered the outer slopes of the area overlooking the Sciara del Fuoco. In addition, splashes were observed on April 27 and May 2, sometimes intense. The average frequency of explosions in the North zone varied between 9 and 17 events / h. The explosive activity of the Center-South zone caused explosions of mainly fine materials (ashes) mixed with coarse materials, with an average intensity (less than 150 m in height) and sometimes high (the products exceeded 250 m in height ). The frequency of explosions in the Center-South zone varied between 5 and 8 events / h.

The amplitude of the volcanic tremor generally had medium-low values, with a decrease from 02/05.

Source : INGV.

Read the whole article ile:///C:/Users/Utilisateur/AppData/Local/Packages/Microsoft.MicrosoftEdge_8wekyb3d8bbwe/TempState/Downloads/BollettinoStromboli20200505%20(1).pdf

Photos : F. Ciancitto, INGV-OE Catania , LGS – Laboratorio Geofisica Sperimentale .


Colombia , Nevado del Ruiz :

Weekly activity bulletin of the Nevado del Ruiz volcano
The level of activity continues at the level of yellow activity or (III): changes in the behavior of volcanic activity.

With regard to monitoring the activity of the Nevado del Ruiz volcano, the COLOMBIAN GEOLOGICAL SERVICE reports that:

The seismicity generated by the fracturing of the rocks showed a slight increase in the number of earthquakes and the seismic energy released, compared to the previous week. This type of seismicity was mainly located in the South-East, North-East and West-South-West sectors of the volcano, as well as in the Arenas crater, at depths varying between 0.6 and 6.1 km. The maximum magnitude recorded during the week was 1.9 ML (local magnitude) corresponding to the earthquake recorded on May 3 at 11:24 a.m. (local time) located 2.0 km south-south-east of the Arenas crater, 3.2 km deep.

Seismicity related to fluid dynamics inside volcanic conduits showed a slight decrease in both the number of events recorded and the seismic energy released, compared to the previous week. This seismic activity was characterized by the occurrence of continuous volcanic tremors, tremor p