September 07 , 2016. EN. Sabancaya , Mauna Loa , Ruapehu , Nevado Del Ruiz .

Home / blog georges Vitton / September 07 , 2016. EN. Sabancaya , Mauna Loa , Ruapehu , Nevado Del Ruiz .

September 07 , 2016. EN. Sabancaya , Mauna Loa , Ruapehu , Nevado Del Ruiz .

September 07 , 2016.



Sabancaya , Peru :

The Sabancaya, located 75 km northwest of the city of Arequipa, is regarded as one of the seven active volcanoes of Peru, his last eruption took place between 1990 and 1998.
This year, 2016, the volcano has shown a volcanic unrest in emissions fumaroles which eventually amounted to 1800 m above the crater and persistent volcanic seismic activity. Furthermore, the volcanic seismic activity was slightly increased in February and August of this year, associated with reactivation of geological faults located in the Colca Valley, near the Sabancaya (February 2013, August 2013 and August 2016).


Recent observations of the Sabancaya, realize that:
A significant increase in the number of earthquakes associated with a slight ascent of magmatic material (earthquakes type « hybrid ») was held for three consecutive days on 25, 26 and 27 August 2016, culminating with a small explosion of 72 megajoules (MJ) of energy on August 27 at 6:51 local time. After the explosion, the Sabancaya issued gray gas, dense, which reached 1000 m above the crater and were dispersed in an easterly direction.
The flow of volcanic SO2 gas was increased to values above 4000 tons / day. The maximum values of recent months was recorded on May 23 (3182 tons / day), June 1 (2763 tons / day), July 3 (2763 tons / day), August 28 (4366 tonnes / day) September 3 (4732 tons / day).


During this year, the columns of fumaroles amounted to heights of 1800 m above the crater. These columns are usually white (steam) and not very dense, though in recent months they have had a higher density and took bluish discoloration that suggest a greater presence of volcanic gases. Moreover, the characteristic of magmatic H2S odor (rotten egg smell) is sensitive to several kilometers.
The emergence and significant increase in emissions of fumaroles are located on the top of the northern flank of the volcano. These points of issue were observed from infrared satellite images, as well as during a field inspection by personnel of the OVI on 25 August, in which were found five areas from which emanate gases whitish. The largest is 750 m northwest of the crater, at temperatures up to 85 ° C and sometimes gas will go up to 500 meters high.

Sabancaya - field fumaroles - photo OVI 08/25/2016

The Sabancaya showed moderate volcanic activity, but increasing, with gases that rise up to 1800 m above the crater, becoming bluish and denser.
During the last week of August, after three days of sudden increase in the number of hybrid-type earthquakes, on August 27 at 6:51 local time, a small explosion occurred on Sabancaya. The energy of this first explosion in 2016 was 72 megajoules.
In recent weeks, the rate of SO2 volcanic gas has been increasing up to values greater than 4000 tons / day.
Today, at least five areas around the volcano, where volcanic gases are emitted are observed, besides the crater.

Maintain the level of yellow alert.
Do not approach the crater or areas where volcanic gases are emitted.
• Implement contingency plans for an increase in volcanic activity Sabancaya.
Make an aerial flight over the volcano to study possible changes in the morphology of the massif and the formation of new emission zones of fumaroles.
Keep informed of the monitoring of the volcanic activity of Sabancaya through reports of the OVS and OVI.
Both institutions, OVS and OVI, monitor volcanoes of Peru, and will continue monitoring to detect evidence of imminent eruption, in which case they will meet immediately with the authorities and the community in general.

Source : OVI , Ingemmet.

Photos : Vic Hanson / Summitpost , OVI.


Mauna Loa , Hawai :

19°28’30 » N 155°36’29 » W,
Summit Elevation 13681 ft (4170 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Activity Summary: Rates of deformation and seismicity at Mauna Loa remain above long-term background levels.

Mauna Loa is not erupting. Global Positioning System (GPS) measurements continue to show ground surface deformations related to inflation of a magma reservoir beneath the summit and upper Southwest Rift Zone, with inflation occurring mainly in the southwestern part of Mauna Loa’s summit caldera magma storage complex. Shallow earthquakes, at depths less than 5 km (3 mi) beneath the south caldera and upper Southwest Rift Zone, continue to be the most frequently occurring type of seismic activity through the past week.

mauna loa

Sulfur, not snow, paints the ground white in the Sulfur Cone area on Mauna Loa’s upper Southwest Rift Zone. The summit of Mauna Loa is over the slope of the mountain out of sight to the left in the background.

Earthquake rates remain elevated relative to previously established baselines. Measurements from a continuously-monitored fumarole site within the summit caldera showed relatively steady fumarole temperatures and no significant changes in either sulfur dioxide or carbon dioxide concentrations in volcanic gas emissions.

A magnitude 4.0 earthquake occurred at 2.4 km depth beneath the summit caldera of the volcano   (04:25 am in Hawaii).
Such relatively large quakes under active volcanoes can (but not necessarily must) be precursors of new eruptions if they are being caused by magma pressurizing rock and fracturing it on its way up. Whether this particular quake is in fact caused by magma movements is impossible to know a priori without further analysis.


Mauna Loa is statistically « due » for an eruption (its last having been in 1984) and increased seismic activity and inflation over the past years have indicated an ongoing period of unrest due to gradual magma recharge.

Source : HVO, Volcanodiscovery.


Ruapehu , New Zealand  :

Ruapehu Crater Lake: Rapid turn around in lake temperature

The active vent-crater at Mt Ruapehu is occupied by a crater lake. Recently the lake has been cooling and we even discussed the possibility of new record low temperatures. The Crater Lake displays temperatures that typically range between about 15 and 40 °C. The lake has cooled to a minimum of 12 °C (15 August) but has now started to heat rapidly. GeoNet obtains temperatures from the lake using a data logger with a temperature sensor in the lake and communications via a satellite link.



In early August we discussed the possibility of the post 1995/1996 Crater Lake reaching a new low temperature as the lake was cooling strongly at that time. The lake reached a new minimum temperature of 12.0 °C on 15 August. For much of August the lake temperature ranged 13-14 °C, occasionally looking like it maybe going to turn and start heating. The temperature was starting to rise, very slowly, in late-August, but with quite a bit a lot of variability. However by 2 September a rising trend was clearly established. The lake temperature is now 17.6 °C.


2016 August low lake temps.JPG

On May 11 2016 the lake reached a high of 46°C, the highest we have observed since it reformed in 1999-2000. This high temperature was also accompanied by volcanic tremor and an increase in the output of volcanic gas. The Volcanic Alert Level (VAL) was raised to Level 2 at that time, lowering to Level 1 in early July when the gas output and volcanic tremor levels declined. About 2 days after the lake temperature started to rise on 2 September, the level of volcanic tremor also started to rise and has remained present since 4 September. The heating and cooling cycles are controlled by a mix of volcano and geothermal processes. Further sampling and visits to the Crater Lake are planned as the weather allows, being part of the standard GeoNet monitoring programme for Mt Ruapehu.

Source : Geonet / Brad Scott



Nevado Del Ruiz , Colombia :

Bulletin of activity of the volcano Nevado del Ruiz, from 30 August to 6 September 2016

The level of activity continues:
At  activity level Yellow or (III): changes in the behavior of volcanic activity.

Regarding the monitoring of the activity of the Nevado del Ruiz, the Colombian Geological Service reports that:

During the past week, different monitoring parameters show that the Nevado del Ruiz volcano remains unstable. Seismicity has been mainly associated with fluid dynamics in volcanic conduits. This activity is mainly located in the vicinity of Arenas crater, east and southeast of it and was characterized by recording episodes of volcanic tremors, which were associated with fluid movements and gas / ashes emissions  into the atmosphere, as it was confirmed on the images captured by the cameras installed in the volcano area as well as by the reports of the responsible of the natural national park of Los Nevados (NNNP) and Service geological Colombian. Ash emission process can occur over several days and sometimes several times a day without involving an individual report for each episode.


In addition, an seismic activity associated with the fracturing of the rock inside the volcano, which was similar to the previous week was recorded. This type of seismicity is mainly located in the seismogenic sources of the North and North distal and, to a lesser extent in the Arenas crater and Northwest areas, Northeast, and South-West of the volcano, to depths between 0.63 and 8.66 kilometers. The appearance of a seismic increase of minor character recorded on September 1, located in the northern sector of the volcanic structure, at depths ranging between 6.09 and 8.11 km is a notable fact. The earthquake recorded with the highest energy on 1 September at 5:13 (local time) associated with this slight increase, with a maximum magnitude of 1.4 ML (local magnitude), was located in the distal part of the northern sector , 7.11 km from the crater, and at a depth of 7.43 km.

nevado del ruiz

The volcanic deformation measured from electronic inclinometers, global navigation satellite systems (GNSS) and satellite images to track changes in the tilt, the position and the shape of the volcano, respectively, continued to record changes.
The volcano continues to emit into the atmosphere large amounts of water vapor and gases, including sulfur dioxide (SO2), as it was felt by the permanent stations SCANDOAS installed in the Volcano area and on satellite imagery. On the satellite images provided by the site Mirova, no thermal anomaly has been identified.
The column of gas, steam and ash from time to time, reached a maximum height of 1800 m above the top of the volcano, on September 4th. The direction of the dispersion of the column was in compliance with the prevailing wind in the area, which during the week showed a predominant direction towards the west and the northwest of the volcano, which promotes dispersion of ashes on people who are in these directions  .

Source : SGC

Photos : Archives SGC

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