March 02 , 2017. EN. Etna , Colima , Nevado Del Ruiz , Piton de la Fournaise .
March 02 , 2017.
Etna , Sicily :
ACTIVITY AT ETNA, 27 FEBRUARY – 1 MARCH 2017
On the late afternoon of 27 February 2017, the Strombolian activity that had started at a vent located in the former « saddle » between the old and new cones of Etna’s Southeast Crater (SEC) showed a rapid increase, and lava overflowed from the vent, forming a flow that descended the south flank of the SEC. This eruptive episode, the first significant eruptive event at Etna since the summit eruptions of May 2016, is still going on as of late 1 March 2017, though at diminishing intensity.
The lava overflow started shortly after 17:00 UTC (= local time -1) on 27 February; initially the lava rapidly spilled down the steep flank of the SEC, but then slowed after reaching the gently sloping terrain at its base, slowly expanding south-southwestward, toward the old cone of Monte Frumento Supino. During the night of 27-28 February, the activity was characterized by frequent Strombolian explosions, which launched incandescent lava fragments up to 200 m above the vent, while lava continued to overflow to the south .
During a field survey carried out by INGV-Osservatorio Etneo staff on 28 February, the eruptive activity continued with minor fluctuations, and there were also sporadic emissions of vapor and brownish ash (old pulverized rock material) from serveral points within the New Southeast Crater (NSEC), whose latest activity had occurred between 6 and 8 December 2015. The lava flow was slowly advancing on top of snow above Monte Frumento Supino, its most distant front at about 2800 m elevation and 1.2 km from the vent . A conspicuous new pyroclastic cone was growing around the active vent, and had already reached a height well above the highest points on the SEC and NSEC, which stand at about 3290 m.
On 1 March, the activity continued with essentially the same characteristics as on the previous day. The most advanced lava flow had stagnated at about 2700 m elevation and little more than 1.5 from the vent. The new pyroclastic cone continued to grow rapidly, both in height and width, and its eastern base had started to fill the depression of the NSEC . On the late evening, the eruptive activity showed a marked reduction in intensity, and the volcanic tremor amplitude diminished rapidly.
Source : INGV
Photos : B Behncke , INGV.
Colima , Mexico :
19.514 ° N, 103.62 ° W
Altitude 3850 m
On 24 February, the University Center for Studies and Research in Vulcanology at the University of Colima reported low intensity explosions on the Colima the previous week. The inner crater was about 250 m in diameter and 50 to 60 m deep. The anterior lava domes were destroyed in late September and mid-November 2016.
Scientists who visited the front of a 4.5 km pyroclastic stream that was set up on January 8 found that the flow had stopped with very little ash and that the local vegetation had not been burned, suggesting that the flow was at low temperature. The Civil Protection Unit of Colima noted that the public should not enter the exclusion zone of 8 km radius, and also stay away from ravines.
Source : GVP
Photo : Hernando Alonso Rivera Cervantes
Nevado Del Ruiz , Colombia :
Weekly activity bulletin of the volcano Nevado del Ruiz, from February 21 to February 27, 2017
The level of activity continues: at the level of activity yellow (III): changes in the behavior of the volcanic activity.
Regarding the monitoring of the activity of the Nevado del Ruiz volcano, the Colombian Geological Survey reports that:
During the last week, various monitoring parameters show that the volcano Nevado del Ruiz continues with unstable behavior. It shows an increase in seismic activity related to fracturing of volcanic rock in the volcanic edifice, both in the number of recorded earthquakes and in the seismic energy released compared to the previous week. The seismic increase was recorded during the period from 23 to 26 February in the southwest sector, at depths between 1.1 and 4.0 km and a maximum amplitude of 3.2 ML (local magnitude). This maximum magnitude value also corresponds to the highest energy recorded during the week, which occurred on 25 February at 08:51 (local time), 2.4 km southwest of the Arenas crater and At 3.4 km depth. It is important to note that the increase in seismic activity mentioned, is the largest so far this year.
With regard to related seismicity in fluid dynamics in the ducts of the volcanic edifice, it continued to be recorded during the week similar rates to the previous week. This type of activity is characterized by the appearance of earthquakes with different levels of energy, long period (LP) and very long period (VLP), several tremors pulses and fluid earthquakes. The earthquakes were mainly located in the Arenas crater and, to a lesser extent, in the South-South-East sectors of the volcano. Some of these seismic signals have been associated with emissions of gases and ash into the atmosphere, as confirmed by the cameras installed in the volcano region and by the reports of the managers of the Natural Park of Los Nevados (Pnnn). The recording of seismic signals of this kind is not excluded, with higher energy levels which may be associated with emissions of gas and ash. It is important to remember that ash emission processes can occur over several days and sometimes several times a day, without involving an individual report for each episode.
Volcanic deformation, measured from electronic inclinometers, Global Navigation Satellite Systems (GNSS) and satellite images to determine changes in tilt, position and shape of the volcano, continues to record In the last few months, a deflationary process and intermittent inflation / deflationary impulses linked to gas and ash emissions.
The volcano continues to emit significant amounts of water vapor and gases, including sulfur dioxide (SO2), as evidenced by the values obtained by the SCANDOAS stations installed in the volcanic zone and On the satellite image. In the tracking information provided by the Mirova and NASA FIRMES site, several weak thermal anomalies, from 21 to 23 and 26 February were identified.
The column of gas, steam and ash from time to time reached a maximum height of 2000 m measured on the top of the volcano on February 25th. The direction of the dispersion of the column was in line with the dominant wind regime in the area, which predominated during the week to the northwest and southwest of the volcano.
The volcano Nevado del Ruiz continues to activity level Amarillo.
Source : Ingeominas.
Photo : César Rios Giraldo
Piton de la Fournaise , La Réunion :
Monthly Bulletin of Wednesday, March 1, 2017
The month of February 2017 was marked by a 28-day eruption that began on 31 January and was halted on 27 February 2017. During this eruption, less than 10 million m3 of lava flows were emitted on the surface (between 3 and 8 Mm3 according to the estimation methods).
The contours (Figure 1) and the volumes of surface flow have changed little during the last two weeks of eruption due to extremely low surface flows in the second half of the eruption (<1 m3 / sec).
Figure 1: Evolution of the extension of the flows during the eruption of 31 January – 27 February 2017. (© OVPF / IPGP)
The deformations associated with magma migration to the eruptive site (January 31st) focused on the southern and eastern part of the volcano and did not exceed 30 centimeters (Figure 2).
Figure 2: Surface displacements associated with magma migration to the eruptive site (January 31st). The vectors represent the horizontal displacements (scale in meters given by the value MAX VECTOR) and the colored circles the vertical displacements (scale in meters given by the colored bar). (© OVPF / IPGP)
During the eruption and since its eruption on 27 February, inflation (swelling) of the terminal cone continues continuously (about 1 cm of elongation of the summit in one month).
At the same time, CO2 concentrations in the soil at the level of the volcano deposit remain high and the deep seismicity (ca -20 km below sea level) under the western flank of the volcano (Plaine des Palmistes) began to increase Since about 17 February.
These parameters demonstrate depth pressurization and upwelling of fluid from the deep to the more superficial storage areas below the summit craters (ca. 2 km below the surface).
Source : OVPF
Photo : Dronecopters