April 13 , 2017. EN. Nevado Del Ruiz , Poas , Aira , Sheveluch.
Nevado Del Ruiz , Colombia :
Weekly activity bulletin of the volcano Nevado del Ruiz, from 4 April to 11 April, 2017
The level of activity continues: at the level of yellow activity or (III): changes in the behavior of the volcanic activity.
As regards the monitoring of the activity of the volcano Nevado del Ruiz, the Colombian Geological Survey reports that:
Over the past week, the various monitoring parameters show that the Nevado del Ruiz volcano continues to show unstable behavior.
The seismicity associated with the fracturing of the volcanic rock beneath the building showed a slight increase in the number of events and the same values recorded in terms of seismic energy released compared to the previous week. This seismicity is mainly located in the South-South-East, North-East and North volcanic distal volcanic zones, and scattered in the southeast of the volcano. The depths of the earthquakes ranged from 1.9 to 7.5 km. The maximum magnitude recorded during the week was 1.9 ML (local magnitude) for the April 4 earthquake at 03:18 (local time), located 1.4 km northeast of the Arenas crater at Depth of 4.1 km. Yesterday and today, episodes of seismicity of drumbeat type that were of short duration and very low levels of energy were recorded. This seismic activity is associated with the rise of domes (magma) on the surface.
Regarding the seismic activity associated with fluid dynamics within the volcanic structure ducts, these remained at relatively similar levels in the number of recorded events and showed a slight decrease in the d ‘energy. This type of activity is mainly characterized by the appearance of earthquakes with varying energy levels and duration, long period type, very long period, volcanic tremor pulses and earthquakes of multiple fluids. Episodes of continuous volcanic, low-energy and short-lived tremors that have been recorded as a result of some of the above events are also recorded. The earthquakes were mainly found in the Arenas crater and its surroundings.
Some of these seismic signals have been associated with emissions of gases and ash into the atmosphere, as confirmed by the images captured by the cameras installed in the volcano area and by reports from Los Nevados National Park officials and Of the Colombian Geological Service who were working on the ground. Recording seismic signals of this type with higher energy levels and which may be associated with emissions of gas and ash are not excluded. It is important to remember that the ash emission processes can occur for several days and sometimes several times during the 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 / deflation impulses, possibly linked to the emission of gas and ash.
The volcano continues to emit significant amounts of water vapor and gases, including sulfur dioxide (SO2), as shown by the values obtained by the SCANDOAS stations installed in the volcano zone, Satellite image analysis. In the tracking information provided by the NASA website and FIRMES Mirova, thermal anomalies were identified on 04, 06 and 07 April.
The column, gas vapor and ash from time to time reached a maximum height of 1500 m measured at the top of the volcano on 10 April. The direction of dispersal of the column was in line with the direction of the wind in the area, which predominated during the week northwest of the volcano.
The volcano Nevado del Ruiz continues to activity level Amarillo.
Source : Ingeominas.
Photos : Archives Ingeominas
Poas , Costa Rica :
On Wednesday 12 April around 6.30 am, the Volcanology and Seismology Research Institute of the National University (OVSICORI) recorded an eruption on Poás Volcano.
Because of the lack of visibility in the area, OVSICORI can not confirm the altitude reached by the column, but the activity lasted for nearly 40 minutes.
The neighbors of the Bajos del Toro area in the northeast of the volcano and the national park have been affected by ash falls and a strong smell.
Preliminarily, the eruption is considered to be a phreatic explosion (vapor), but the ejected material must be analyzed in order to accurately determine the nature of the explosion.
The National Emergency Committee (NEC) evacuated residents living near the Desague River, which originated from the South of the active crater, causing the material to fall into the river, causing a small flood And a small flood, which is why the CNE decided to evacuate the inhabitants.
Poas volcano has increased its activity over the last few days, OVSICORI has also reported the emergence of a new fumarole which may have contributed to the rise in the temperature of the lake from 35 ° C 40 ° C in one week, with its color also changing from green to milky gray.
Source : News .cr.
Photo : Javier Pacheco.
Aira , Kyushu , Japan :
Elevation 1117 m
JMA reported that an explosion from the Minamidake summit crater (at Aira Caldera’s Sakurajima volcano) at 1004 on 4 April generated an ash plume that rose 1.2 km above the crater rim. During field work later that day, scientists observed ashfall in Sakurajima Koike-cho in Kagoshima (3 km NW). The Alert Level remained at 3 (on a 5-level scale).
SAKURAJIMA VOLCANO JAPAN: Mt Sakurajima erupting, February 15, 2011.
Sakurajima is an active composite volcano (stratovolcano) and a former island in Kagoshima Prefecture in Kyushu, Japan. The lava flows of the 1914 eruption caused the former island to be connected with the Osumi Peninsula.The volcanic activity still continues, dropping large amounts of volcanic ash on the surroundings. Earlier eruptions built the white sands highlands in the region. As of September 2015, the volcano is under a Level 3 (orange) alert by the Japan Meteorological Agency, signifying the volcano is active and should not be approached. The most recent eruption started on February 5, 2016.On September 13, 2016 a team of experts from Bristol University and the Sakurajima Volcano Research Centre in Japan suggested that the volcano could have a major eruption within 30 years.
Source: Japan Meteorological Agency (JMA) , Vulcanologia Esia.
Photo : wdeon / Shutterstock.com
Sheveluch , Kamchatka , Russia :
Elevation 3283 m
KVERT reported that during 1-6 April lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images showed a daily thermal anomaly over the dome, and ash plumes that drifted 20 km SE on 3 April. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).
Source: Gvp , KVERT
Photo : Yu Demyanchuck , IVS FEB RAS , KVERT ( 2015)