October 21 , 2017. EN.  Nyiragongo , Panchon Peteroa, Sierra Negra , Ticsani .

Home / blog georges Vitton / October 21 , 2017. EN.  Nyiragongo , Panchon Peteroa, Sierra Negra , Ticsani .

October 21 , 2017. EN.  Nyiragongo , Panchon Peteroa, Sierra Negra , Ticsani .

October 21 , 2017.

Nyiragongo , Democratic Republic of Congo:

An intense volcanic activity has been observed since Tuesday in Goma, a city in the eastern Democratic Republic of Congo, located in the area of ​​?? activities of the famous volcano Nyiragongo, according to experts who currently exclude a risk of eruption .
« The Nyiragongo and Nyamulagira volcanoes have experienced intense activity in their respective craters » Tuesday and Wednesday, said a statement from the OVG, Volcanic Observatory of Goma, capital of the province of North Kivu.
« This activity has evolved down until Friday morning, » the statement said, adding that « the different teams of OVG scientists are closely monitoring this situation both in the field and in the laboratory. »
The alert level is yellow, « the population must continue to quietly go about their business. »
« This is an exceptional activity, all activity is concentrated in the crater of Nyiragongo », one of the most active and dangerous volcanoes in Africa, told AFP Célestin Kasereka, scientific director of OVG.

Inside the volcano, the lava flows from a small vent recently appeared to the big well, he explained: « There is no concern on the side of the volcano, there is no fumaroles « .
Rumors of a possible volcanic eruption were circulating on social networks and in Goma, a city regularly rife with Nyiragongo eruptions overhanging it, located about twenty kilometers to the north.
On July 3, more than a thousand people participated in an evacuation exercise in the event of a volcanic eruption in Goma.
The last eruption of Nyiragongo, more than 3,000 meters high, dates back to January 17, 2002. It caused the death of more than 100 people, covering almost the entire eastern part of Goma, including half of the airport runway of the city.
The most deadly eruption occurred in 1977 with more than 600 deaths.

Source : Africatimes
Photo : Danielle Hart Smith


Planchon Peteroa , Chile : 

During the first fortnight, forty-five (45) events related to fracturing processes of rigid materials called volcano-tectonics (VT) were recorded, with a local magnitude (ML) of 2.4. The locations of the earthquakes were concentrated mainly under the volcanic building at depths between 3.5 and 7 km. The strongest earthquake was located 1.8 km northwest (NW) of the main crater at a depth of 5.2 km.
With respect to fluid dynamics events, one thousand nine hundred and ninety-nine (1999) long-period (LP) seismic events with local amplitudes (ML) of less than 1.5 and values ​​of maximum reduced displacements (DRC) of 5.7 cm 2, considered low value, while the dominant frequencies were kept between 0.6 and 1.7 Hz mainly.
The images of the IP cameras showed the presence of small, low-energy, whitish degassings whose heights did not exceed 50 m above the active crater of the complex.
From the data obtained by two (2) GNSS stations, which measure the deformation of the volcanic complex, no significant variation was observed. On the other hand, the data provided by one (1) electronic inclinometer installed on the complex did not show any variations related to the morphological changes of the volcano.

No anomalies have been reported in sulfur dioxide (SO 2) emissions to the atmosphere in the volcanic complex sector, according to data obtained by the Ozone Monitoring Instrument (OMI) Sulfur Dioxide Group (S02). http: //so2.gsfc.nasa .gov /) and the National Service for the Environment, Data and Satellites (NESDIS) (http://satepsanone.nesdis.noaa.gov).
No thermal warnings were reported in the volcanic complex area according to data published by the Middle Observation InfraRed of Volcanic Activity (Mirova) on its website (http://www.mirovaweb.it/).

Although the level of seismicity recorded during this period is in line with previous records, recorded energy levels are considered to be above baseline levels. The parameters suggest that this activity is associated with the dynamics of a magmatic body interacting with the superficial hydrothermal system. There is the possibility of an evolution towards an interaction of the two systems generating explosive activity and low to moderate ash emissions that could affect the area of active craters. For all this, it is recommended to restrict access to a zone of 1 KM around active craters.
The level of volcanic alert remains at the level: AMARILLO, changes in the behavior of the volcanic activity.

Source : Sernageomin


Sierra Negra , Galápagos Islands, Ecuador :

Special Report Sierra Negra N.- 1 – 2017

On the evening of October 19, 2017, at 18:07 (Galapagos time) the seismic monitoring network of the Galapagos Islands Geophysical Institute detected an earthquake of magnitude M3.8 whose epicenter was in the caldera, at the Northeast edge from Sierra Negra, in the vicinity of Chico volcano. This earthquake was followed by four identical replicas that occurred within one hour. All these replicas have epicentres in the vicinity of the Sierra Negra caldera. The main earthquake had a depth of 16 km.

Figure 1. Epicentres of earthquakes recorded on the night of 19 October.

Sierra Negra is a shield-type volcano that is located in the south of Isabela Island, the largest of the islands. This volcano is home to a caldera with an area of ​​82 km2. The last eruptions of Sierra Negra took place in 1979 and 2005. After this eruption, a process of inflation and deflation within the volcano was detected, the same as that associated with the magma intrusion impulse. shallow depth (a few kilometers below the floor of the boiler.). The Chico volcano is located on an edge of the Sierra Negra. The Institute of Geophysics currently maintains a seismic network of 4 stations for monitoring volcanoes and island tectonic faults.

While seismological and geophysical studies have shown that the crust under the Galapagos platform is 15 km thick (Villagomez et al., 2011 and Tepp et al, 2014), the main earthquake was located just below the crust, in an area of ​​low seismic velocities composed of a soft zone where magma accumulates

Source : IGEPN


Ticsani , Peru :

Seismic monitoring:
• VTP (Proximal Volcano – Tectonics) type seismicity, which denotes rock fracturing activity, continues to decline. Its frequency rate has increased from 11 VTD / day (Report n ° 18-2017) to 7 MTB / day on average for this fortnight.
During this period, VTD earthquakes (distal volcano-tectonic earthquakes) increased, averaging 18 VTD / day as a result of a seismic swarm located southeast of the volcano crater.
Occurrence of Hybrid events on the Ticsani volcano is sporadic. These events are associated with magma movements inside the volcano. The activity of Hybrid events is very weak and during this period only 3 low energy events were observed.

Location of the event:
The spatial distribution of seismicity has two groups or seismic foci: the first, group A, is located near the Ticsani volcano, with mainly proximal earthquakes. A second group, the B, is also observed, consisting of distal earthquakes recorded for the most part on 2 October and corresponding to a seismic swarm. The depth distribution reaches 17 km from the surface. The earthquake that stood out during this analysis period was recorded on October 2nd at 10:43 HL (local time), and had a local magnitude of 2.7 ML. It was located 14 km southeast of Ticsani.

Satellite monitoring:
SO2 anomalies: The GSDM-NASA « EOS Aura » satellite system (http://so2.gsfc.nasa.gov/) recorded low SO2 gas density values ​​during this period.
Thermal anomalies: The MIROVA system (www.mirovaweb.it) did not detect thermal anomalies on the Ticsani volcano (VPR = 0 megawatts).

Seismic activity in the Ticsani region remains weak. The predominant type of events on the volcano is related to rock earthquakes, located far from the crater of Ticsani.
During this period, VTD earthquakes had an average occurrence rate of 18 VTDs per day, with the recording of a distal earthquake swarm on 2 October. On the other hand, VTP proximal seismicity has decreased.
In the spatial distribution of seismicity, two groups were observed: the first near the Ticsani volcano (VTP) and a second located 17 km southeast of Ticsani, corresponding to the earthquake swarm of 2 October.
Any changes will be reported in a timely manner.

Source : IGP

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