December 04 , 2016. EN. Misti , Cayambe , Santiaguito , California Volcanoes .

Home / blog georges Vitton / December 04 , 2016. EN. Misti , Cayambe , Santiaguito , California Volcanoes .

December 04 , 2016. EN. Misti , Cayambe , Santiaguito , California Volcanoes .

December 04 , 2016.

 

Misti, Peru :

Date: December 1, 2016
Update of main activity observed from 01 to 30 November

The Misti is an active, young, explosive volcano and is considered the highest risk volcano in Peru because of its proximity to the city of Arequipa (~ 17km), with a population of about one million inhabitants and a very important infrastructure nearby (dams, hydroelectric plants, airports, mining centers, etc.). Over the past 600 years, the volcano has experienced at least one major explosive eruption and a dozen fumaroles crisis.

OVS-PGI, during the last 11 years of real-time seismic monitoring, has drawn a « baseline » which is now used to compare and track the daily seismic activity of the Misti volcano.

misti

Summary for the month of November 2016.
Seismic and volcanic monitoring:

The seismic activity of the Misti volcano during this period remains at low levels:
VT events, associated with rock fracturing within the volcano, showed a slight increase compared to the previous period (01-31 October). Their average daily occurrence rate varies between 11 and 17 VT per day.
LP events, associated with fluid dynamics (gas and vapor), continue to show a low level of activity. Their average daily occurrence rate is less than 5 LP per day and their energy is less than 1 MJ (MJ = megajoule).
On the other hand, the activity of type Tremor showed a slight increase compared to the previous period, going from three to four episodes per day. Most Tremor-type activities correspond to 27 November, with 21 representative cases. These events were characterized in time (<10 minutes) and low energy

 

 misti

Regarding the evolution of the total daily seismic energy, associated with the total activity of the Misti volcano, a greater variation was not observed, remaining at a low level.
November 8 at 10:40 am HL (Local Time) an high-energy VT event, generated by a magnitude of 1.7 ML (ML = local magnitude) was detected, and was located 0.5 km below the main crater.

Satellite Tracking:
Thermal anomalies: The Mirova system (www.mirova.unito.it) of the University of Turin (Italy) has not detected thermal anomalies on the Misti volcano this month.
SO2 Anomalies: The « EOS Aura » GSDM-NASA satellite system (http://so2.gsfc.nasa.gov/) did not detect significant anomalies of SO2 (magma gas) density for the period in progress .

Source : IGP

Photos : Mapio , ERNESTO BENAVIDES / AFP

 

Cayambe , Ecuador :

Seismic anomalies:
SUMMARY

On June 5 of this year, there was an increase in the number of VT type seismic events (generated by rock fracturing). This swarm was reported in the special report released on June 22 this year. This activity took place in the form of a swarm (several earthquakes of similar magnitudes produced in a short period of time), which was located in the northeast, outside the volcano, and near one of the most active fault systems across Ecuador (Chingual fault system).

This activity decreased gradually and returned to base level during the month of August. From the beginning of September, it was again observed a slight gradual increase, but that was more marked in recent weeks.

 

 cayambe

In recent days, several volcano-tectonic events have been recorded. In particular, on November 14, with an earthquake of magnitude M3.3 which was located under the volcano and on 27, with another earthquake of magnitude M3.6, also under the volcano and slightly felt in the upper areas of the volcano edifice. These two events are particularly abnormal because of their magnitude. With the earthquake that took place on the 27th, a swarm of volcano-tectonic earthquake, which lasted two hours was noted. The seismicity continued, but with less intensity, without returning to its basic level. The location of earthquakes since September has changed from that observed in June, as most are located directly under the volcano. This migration of seismicity is something that has been observed in other volcanic systems, sometimes before the beginning of a period of eruptive activity, such as on the volcano Guagua Pichincha in 1998-1999. However, the fact remains that this type of activity migration events does not necessarily end in eruption, as in Cotopaxi in 2001.
In addition, in this last period reports were received from climbers on an increase in the smell of sulfur which is perceived much stronger than in previous months.
Given the characteristics of the current activity observed, this could be related to a disturbance of the volcano, possibly with a magmatic component that would be modifying the hydrothermal system. If this disturbance is maintained at the same levels, it could trigger a small eruption (months) with characteristics similar to those presented on the Cotopaxi volcano in 2015.
The other possible scenario is that the abnormal activity returns to the level of the base, in which case the probability of an eruption would be very distant.
These scenarios may change over time depending on the monitoring data recorded on the volcano. The evolution of these scenarios will be presented through the special reports that will continue to be issued according to the activity of the Cayambe volcano.

TECHNICAL REPORT

INTRODUCTION
On 22 June of this year, the Cayambe Volcano Institute of Geophysics in its Special Report No. 1, reported the emergence of a seismic anomaly on the volcano. Following this report, the Institute of Geophysics worked on the analysis of seismic data and continued with intensive monitoring of the various parameters. The surveillance network of this volcano consists of three seismic stations, one GPS station and one inclinometer. Surveillance, especially seismic, began in the 1980’s. All stations arrive at the IG-EPN in real time.

 

Informe Especial Cayambe N. 3 - 2016

Figure 1. Cayambe volcano monitoring network, consisting of seismological stations operating since 1995, and GPS and inclinometer stations to measure deformation of volcanic flanks.

SEISMIC ACTIVITY

Figure 2 shows an update of the seismic activity recorded in recent months, where it is observed that, after the increase recorded during the month of June, it has fallen back to the baseline for Cayambe.
The sequence of events recorded in June responds to a so-called distal seismic swarm. There is a main event of higher amplitude in which smaller events (like replicas of the typical sequence) are generated. It is distal because it was not placed under the volcano, but in the northeast of the latter (FIG. 3). In June, a total of ~ 2,300 earthquakes were recorded, being the largest number of events recorded on the volcano since the beginning of seismic monitoring.
In September, there was an increase in activity (Figure 2), with the presence of short – lived seismic swarms formed by volcano – tectonic earthquakes. In addition, the events that could be located were located under the volcano. As of this month, the level of seismicity has continued and has not regained its previous level base. It should also be noted that the location remains the same under the volcano.

Informe Especial Cayambe N. 3 - 2016

Figure 2. Total number and type of daily earthquakes of the Cayambe volcano from May 1, 2016 to November 28, 2016. Columns are separated between event types (VT = volcano-tectonic, LP = long period, TREM = Episodes of tremors and HB = hybrid).

This change corresponds to the occurrence of VT-type earthquakes which have increased from an average of 24 / day to 35 / day and LP-type earthquakes (generated by fluid movements), which are From 9 / day to 13 / day.
On the other hand, in November, 2 major earthquakes of magnitude on the volcano were noted, the first took place on 14, with a magnitude of M 3.3 (Ml) and the second on 27 A magnitude of M 3.6 (Ml), the latter was felt by some people. Both events were located under the volcano. In addition, after the 27 earthquake, a swarm of tectonic events under the volcano that lasted about 2 hours and was followed by many scattered events was recorded.

The location of earthquakes since September is also a feature of the current seismicity because they are located under the volcano as seen in Figure 3 and which differs from those that arrived in June.

Informe Especial Cayambe N. 3 - 2016

Figure 3: Events near Cayambe volcano since early June 2016. Events in Blue took place in Special Report No. 1 (June 22). The yellow events are new, in recent weeks.

Deformation:

GPS
The processing of CYMI Station data (Figure 1) in recent weeks does not show a signal strong enough to indicate a variation associated with volcanic activity (Figure 4). In the chronology, dominates the general trend that is related to the post-seismic signal effect of the April 16 earthquake. However, it should be noted that the vertical component of the time series indicates a displacement of a few millimeters in the positive direction (upward), but it is not yet observed an acceleration of this movement (precision of the vertical component + / – 5.5 to 7 mm). To be sure that there is variation, it is necessary to see a constant trend of change, greater than the error associated with the method (more than 7 mm from the usual level) for more than once a week , Which is not observed at this time.

Informe Especial Cayambe N. 3 - 2016

Figure 4: Time series of the GPS station « CYMI ».

Inclinometry:
The deformation data of the inclinometers show a small change that is visible. This trend is external and related to changes in temperature that influence this type of instrument (Figure 5). In this case, it is also necessary to observe for several days whether this behavior is maintained.

Informe Especial Cayambe N. 3 - 2016

Figure 5: Deformation data recorded using the military Cayambe inclinometer station (Caym).

GAS EMISSION
There were five separate reports of climbers indicating a strong odor of sulfur. The June reports were only about increasing the odor of « rotten eggs » in the highlands of the volcano.  In the most recent reports of November, it is stated that the odor of « rotten eggs » emanates directly from fissures in the glacier and is persistent throughout the volcano.

Two reports also indicate that the strongest odor is recorded in the Picos Jarrin area (5300 meters) and even indicates that mountaineers who were affected by the gases had symptoms of toxic gas inhalation (headaches , Nausea and vomiting).
For the assessment of the intensity of gas emissions, the Institute of Geophysics installed on 1 December a DOAS Permanent Station, which will measure sulfur dioxide.

 cayambe

INTERPRETATION
The current interpretation of June activity is that earthquakes near the fault zone may be associated with volcanic events called distal tectonics, which relate to a change under the volcano, Field of stress around and it pulled the seismic activity on the fractures. The current seismicity is directly associated with this change because, as indicated, it is directly under the volcano and may be generated by a magmatic intrusion that would disrupt the hydrothermal system (see Figure 3).
The scenarios posed for this volcano, with the current conditions are the following:

Considering the characteristics of the current activity observed that it could be related to a perturbation under volcano, possibly with a magmatic component that would be modifying the hydrothermal system. If this disturbance is maintained at the same levels, it could trigger a small eruption (months) with characteristics similar to those presented on the Cotopaxi volcano in 2015.
The other possible scenario is that the abnormal activity returns to the level of the base, in which case the probability of an eruption would be very distant.

These scenarios may change over time based on monitoring data. The evolution of these scenarios will be presented through special reports that will continue to be issued based on Cayambe’s business.
The Institute of Geophysics is working to improve the monitoring network by installing new stations (DOAS, seismic, GPS).

Source : MP / SH / SH / AA / MS
Geophysical Institute
Ecole nationale polytechnique

Photos : Fabricio Guzmán T.

 

Santiaguito , Guatemala :

Activity type: Pelee
Morphology: Complexes of dacitic domes.
Geographical location: 91 ° 34 33˝Latitude N; Longitude W.
Height: 2,500 m
Weather conditions: Clear.
Wind: 5 kilometers per hour
Precipitation: 0 mm

santiaguito

Activity: The dome of the Caliente crater was observed with moderate degassing. It has been observed from low to moderate explosions, emitting plumes of ash at 3300 meters. (10,823 feet) spreading to the south with the generation of ash falls on the Fincas San José Patzulin, Quina and on the foothills of the Santa Maria volcano. These explosions sometimes generated slight degassing noise with a frequency of about 15 seconds.

Source : Insivumeh

photo : .sf.co.ua

 

California Volcanoes , United States :

Current Volcano Alert Level: all NORMAL
Current Aviation Color Code: all GREEN

Activity Update: All volcanoes monitored by CalVO using telemetered, real-time sensor networks exhibit normal levels of background seismicity and deformation. Volcanoes monitored include Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Volcanic Region, Coso Volcanic Field, Ubehebe Craters, and Salton Buttes.

 

ubehebe crater

Ubehebe Craters.

 

Observations for November 1, 2016 (0000h PST) through November 30, 2016 (2359h PDT):
Mt Shasta: One earthquake at or above M1.0 was detected (M2.37).
Medicine Lake: One earthquake at or above M1.0 was detected (M1.07).
Lassen Volcanic Center: Five earthquakes at or above M1.0 were detected, with the largest registering M1.49.
Clear Lake Volcanic Field: No earthquakes at or above M1.0 were detected. [Note: The typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was M3.33].
Long Valley Volcanic Region: In Long Valley Caldera, 12 earthquakes of M1.0 or greater were detected, with the largest event registering M2.86. Three earthquakes at or above M1.0 were detected in the Mono Craters region, with the largest registering M1.63. No earthquakes at or above M1.0 were detected under Mammoth Mountain. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M2.83].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Forty earthquakes of M1.0 or greater were detected, with the largest registering M2.95. Many of these events occurred during a minor seismic swarm on November 15, 2016 about 6 miles northwest of the town of Calipatria.
Coso Volcanic Field: The typical high level of seismicity was observed, with 28 earthquakes M1.0 or greater. The largest registered M2.87.

The U.S. Geological Survey will continue to monitor these volcanoes closely and will issue additional updates and changes in alert level as warranted.

Source : Calvo

Photo : themarkeworld.com

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Comments
  • Pamela Conley
    Répondre

    Misting reminds me of Mount Rainer in Washington State in regards to the proximity to towns. Albeit, it is not as active.

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