News from Fuego, Nevado del Ruiz, Sakurajima and Stromboli.

INSIVUMEH recorded in Fuego / Guatemala 5 to 12 moderate explosions of Strombolian type per hour which generated a plume of gray ash which reached approx. 4,500 m-4,700 m asl and derivative W and SW.

In addition, a white plume that reached 4,300 m asl and drifted west and southwest is observed.

The incandescent material is ejected at an approximate height of 100 m to 200 m above the crater with moderate avalanches around the crater, mainly in the Seca, Taniluya, Ceniza, Santa Teresa, Trinidad, Las Lajas barrancas, with slight fallout.

A lava flow 300 meters long is described in the Ceniza barranca, with moderate to strong avalanches from the flow front.

Ash falls have been reported in several leeward areas, including Santa Sofía, Morelia , Panimaché I and II , Finca Palo Verde, San Pedro Yepocapa , Sangre de Cristo and El Porvenir .

Source: Gobierno de Guatemala, Insivumeh / 26.02.2020

According to the Servicio Geologico Colombiano, the seismicity linked to the dynamics of fluids, inside the volcanic conduits of Nevado del Ruiz, presented this week an increase both in the number of recorded events and in the seismic energy released, compared to the previous week. This seismic activity has been characterized by the presence of continuous volcanic tremors, pulses of volcanic tremors, long and very long period earthquakes. Some of these signals were associated with gas and ash emissions, confirmed by cameras installed on the volcano and by reports from field staff and officials of the Los Nevados National Natural Park.

The seismicity generated by the fracturing of rocks (volcano-tectonic) has increased in number of earthquakes and in seismic energy released, compared to the previous week. This type of seismicity was localized in the South-South-East, North-West and in the Arenas crater and, to a lesser extent, in the North-West and South-West sectors of the volcano. The depth of the earthquakes ranged from 0.8 to 6.3 km. The maximum magnitude recorded during the week was 1.7 ML (local magnitude), corresponding to the earthquake recorded on February 19 at 9:31 p.m. (local time), located 2.3 km southeast of the crater. Arenas, at a depth of 3.5 km.

The deformation of the volcanic surface, measured from GNSS (Global Navigation Satellite System) stations, did not show any significant change or deformation process during the week. However, it is important to note that some minor changes have been observed in the data obtained by the inclinometers.
In tracking information from the Mirova and NASA FIRMS web portals, the latter have reported moderate energy thermal anomalies on the volcano in the past week. Sentinel-5 P / Tropomi recorded these 24 and 26.02.2020 high emissions of sulfur dioxide.

The Nevado del Ruiz volcano continues at the yellow activity level.

Source: Ingeominas

At Sakurajima, activity is not weakening ... with this February 27 at 1:07 p.m. and 2:23 p.m. ash plumes of medium volume, drifting south.

Source: JMA
 

Stromboli activity bulletin for the week of 17 to 23.02.2020

In light of the monitoring data, it is highlighted:

Normal activity was observed during this period of explosive strombolian type accompanied by degassing. The hourly rate of explosions fluctuated between average values ​​(12 events / h on February 21) and high values ​​(21 events / h on day February 17). The intensity of the explosions was mainly medium to high in the region of the North Crater and medium in the area of ​​the Center-South crater.

In the morning of February 21 and 22, 2020, INGV-OE staff carried out an inspection to monitor the explosive activity and the morphological changes of the crater terrace.

Here are some considerations on the observations:

In the area of ​​the North crater, the crater N1 presented a flared cone with a slight opening on the NE side. During the hours of observation, it produced explosions of medium to high intensity (many explosions the products reached 200 m in height) with expulsion of coarse materials (lapilli and bombs) with abundant fallout on the sides. The N2 crater showed a cone of regular shape with greater erosion and deepening than during the previous inspection (January 13, 2020) produced an explosive activity of coarse matter of low intensity (less than 80 m high).

In the area of ​​the Center-South crater, crater C showed a pit crater from which breath activity was observed. The crater S1, overlooking the Sciara del fuoco, showed a larger and deep crater compared to the previous inspection, it produced some explosions of gas under pressure with a modest part of fine materials (ash) of low intensity (less 80 m high). The S2 crater showed explosions of mainly fine materials sometimes mixed with other coarse, low intensity.

It was noted a deepening of the craters N2, S1 and S2

The seismological parameters do not show significant variations. There has been an increase in the number of landslide signals in the past week. Soil deformation monitoring networks have shown no significant change to report for the reporting period.

The flow of SO₂ is at an average level. The CO₂ / SO₂ ratio is at an average value (last update on 02/09/2020).

Source: INGV OE