03/04/2016. EN. Cotopaxi , Piton de la Fournaise , Telica , Kanlaon .
Cotopaxi, Ecuador :
In recent weeks a decrease in the number of events is observed, recording daily least 20 earthquakes , volcano-tectonic types (VT), between 1 and 6 earthquakes hybrid type (HB), and 1 to 3 internal explosions. However, the size of these events remained similar to that recorded in January and February, with magnitudes between 2.8 and 1 Mlv. These events are between 2 and 9 km below the crater.
GPS stations on the western flank (CAME, NAS1) and the eastern flank (TAMB) show a movement from West to East (O-E) that are not observed in other stations. This movement could be associated with a small disturbance inside the volcano that can be associated with a rearrangement of magma. However, the evolution of the movement in the vertical component can not be a clear indication of the rise of magma (inflation).
There has been a steady decline of the daily flow of SO2 from December 2015). At the end of March, there was a slight increase, however, these values are in background levels observed since 2011
The number of valid measurements recorded on the station showing the greatest flow value of SO2 shows a downward trend from December 2015 .These last month, it was not detected by satellite observations SO2 emission due to the decrease in the amount of emitted gas. Even the gas measurement by the mobile stations DOAS failed to detect the presence of SO2.
In recent weeks, visual observation conditions were mostly unfavorable weather with high clouds. The surface activity was mainly characterized by a low energy gas emission sometimes reaching up to 900 m above the crater.
So far, observations show the continuation of glacial melt process initiated during the explosions that started in August 2015. The presence of water and humidity is maintained at the base of the glacier fronts generated by the merger. These thin fillets are flowing water on the sides to the main drain. In the last flyby of January 26, 2016, it was obvious that the glaciers continue to suffer from displacement in the downward slope with cracks and formation of fractures.
Since November 23, 2015, no significant ash fall s associated with volcanic activity has been recorded. Small emissions of January probably did not cause measurable ash fall in the vicinity of the volcano.
Regarding the temperatures of different parts of the cone where routine monitoring is carried out, in general, it may be noted that the values of TMA (high apparent temperature) measured on 26 January 2016 are slightly lower than those measured previously especially compared those months of September and October 2015, when they reached their highest values. On the upper flanks, the most important impact on the cone were accelerated loss of glaciers, almost continuously observed on the glacier between Yanasacha and south summit. In addition this phenomenon apparently weakening of the upper walls on the lateral flanks, in which the lack of ice cover causes the phenomenon of detachment and fall of the material of the sidewalls.
Left: Thermal image showing TOMA temperature of 51.9 ° C at the bottom of the inner crater. Right: corresponding visible image, the presence of steam emission decreases the real value of the temperature at the crater. (Photo / Photo: Ramon P. IG / EPN, 01/26/2016).
Because varying intensity of rains occurred around the Cotopaxi volcano, it was recorded 58 secondary lahars since August 2015. Most of them are descended from the West and Northwest sides, mainly by Cutzualo ravine located west of the volcano, which joined the Agualongo near the bridge that is on the road in the National park of Cotopaxi.
Most of the time these lahars are very small and have a lower throughput than 5 m³ / s. Limited to areas in the national park in general, they do not pose a threat to populated areas and infrastructure. Sometimes the most powerful events (> 30 m³ / s) were observed and lahars have invaded the road.
The largest number of lahars took place in November 2015 and February 2016, with 13 events.
After the lahar which occurred on January 13, 2016, which was the most powerful recorded event and invaded the runway (reported in the Special Report # 2), it has not been re-recorded events of this kind because the rain does not have very high intensity. Lahar flows that took place during the months of February and March 2016 were in average (5 m³ / s), except the last recorded stream which had a rate of 20-25 m³ / s and had place on March 19.
Cotopaxi – 08.18.2015 / 17h00 – taking from La Vaquería Ticatilín. SW of the volcano – photo Jose Luis Espinosa–Naranjo
The monitoring data obtained until 28 March 2016 confirmed that some monitoring parameters (SO2, LPs, tremor, ash) returned to the level of pre-eruptive base. All these parameters are related in some way to the gas outlet. The deformation of the volcano marks a break from November 2015, but has not returned to pre-eruption level and ultimately a new small anomaly possibly associated with the reorganization of deep magma is observed. This suggests that part of the magmatic intrusion responsible for eruptive activity between August and November 2015 remains in depth. The number of VT type of earthquakes has decreased compared to previous months, but not their sizes. In addition, small internal explosion continue to be recorded, indicating that persists a pressure source inside the volcano.
Source : IGEPN
Photos : IGEPN , José Luis Espinosa-Naranjo .
Piton de la Fournaise , La Réunion :
Bulletin of activity,
Review of the period from 9 February to 1 April 2016:
The seismometers network of OVPF recorded over the period of last two months 32 summital earthquakes (0.5 / day – below the summit of the volcano), 4 deep earthquakes (0.5 / week – under the volcano), 1247 collapses (21 / day – in the crater Dolomieuon the Nez Coupé of Sainte Rose and near Kala and Pele cone), and 23 local earthquakes in the area of the Roche Ecrite , Piton des Neiges or Volcano. Only some sufficient intensity earthquakes have been located (Figure 1).
Figure 1: seismicity of the island of La Réunion from 01/02/2016 to 03/31/2016 . These numbers show a relatively small volcano-tectonic activity.
Following the remarkable inflation phase at the end of January 2016, a slight deflation of the summit area and the base of the cone is observed from the second week of February 2016.
However, a trend of inflation over the long term is still observed in the far field.
For recall the deformation when it is registered by network measurements at the top and at the base of the cone (about 2000 m) is related to a formal constraint (inflation) or conversely reduced stress by surface source (room or magmatic complex closest to the surface).
Conversely, the network far field shows pressure variations from a deep source.
Therefore, the records as mentioned above allow to assume a localized deep magma source maintaining the edifice under pressure (even with a significant increase in this pressure).
The most significant changes are in the CO2 stream. A continued increase in CO2, both at ground level (in the Plaine des Caffres, the Plaine des Palmistes and Plaine des Sables) and at the level of fumaroles (at the top). Increasing CO2 on the distal station (Plaine des Palmistes) is continuous since the end of the last eruption. Those in OVPF at Gite du Volcan and at the summit date from mid-February – early March.
At the top , the SO2 levels increase only marginally.
Remember, CO2 is a gas that is released in greater depth than the SO2 that it is more superficial.
As in the case of deformation, the records as mentioned above allow to assume that the magma is still deep. This is in accordance with the four deep earthquakes recorded since late February.
Source : OVPF
Photo : Jean Guichard / Maxiscience .
Telica , Nicaragua :
More explosions in the Telica volcano; recommendations say do not approach
2 APRIL 2016. New explosions occurred April 2 in the Telica volcano, northwest of Nicaragua, and the country’s experts have recommended the public not to approach the crater. The blasts occurred the morning of Saturday, when the volcano ejected gases, said geologists from the Seismological Network of Nicaragua.
« The microseismicity present in the volcano is high, incandescence is also observed in the crater floor, we recommend the population and tourists not to approach the crater, » the Red.
Telica volcano is 1,061 meters high and located 112 kilometers northwest of Managua, and is one of the most active volcanoes in Nicaragua. It maintains it’s current activity since last May. Its eruptive process has not caused damage so far, although it is able to put at risk dozens of communities around the volcano.
That volcano is one of three that remain with eruptive activity currently in Nicaragua.
Source : La Prensa
Photo : mashipura.com
Kanlaon , Philippines :
KANLAON VOLCANO BULLETIN 03 April 2016 8:00 A.M.
In the past 24 hours, Kanlaon Volcano’s seismic monitoring network recorded six (6) volcanic earthquakes and a long-duration volcanic tremor that began on 01:30 AM 30 March 2016 and continues with decreasing seismic energy.
Moderate emission of white steam plumes that rose up to 500 meters drifted southwest was observed coming from the active vent. Ground deformation measurements by Kanlaon’s GPS network as of 14 March 2016 indicated slight inflation of the Kanlaon edifice since December 2015.
Alert Level 1 status remains in effect over Kanlaon Volcano, which means that it is currently in a state of unrest probably driven by hydrothermal processes that could generate more minor eruptions.
Source : Phivolcs.
Photo : Jigz.