October 04, 2015. English . Nevado Del Ruiz, Kilauea, Krakatau.

Home / blog georges Vitton / October 04, 2015. English . Nevado Del Ruiz, Kilauea, Krakatau.

October 04, 2015. English . Nevado Del Ruiz, Kilauea, Krakatau.

October 04, 2015.



Nevado Del Ruiz, Colombie :

Weekly Activity bulletin of volcano Nevado del Ruiz:
Subject: activity level of the Nevado del Ruiz volcano.

Activity level Yellow or (III): changes in the behavior of volcanic activity.

Regarding the monitoring of the activity of the Nevado del Ruiz volcano, the SERVICIO Geologico COLOMBIANO through the OBSERVATORIO VULCANOLÓGICO Y SISMOLÓGICO OF MANIZALES, reports that:

During the last week, the volcanic system continued to present instability in his behavior. The recorded seismic activity was mainly associated with fluid dynamics in volcanic conduits. This seismic activity has been characterized by the recording of LP type earthquakes (long time) and episodes of volcanic tremor of short duration, but with significant energy levels. These have been primarily associated with gas emissions and ash into the atmosphere. Some pulses of tremor associated with ash emissions have been verified through the web cameras installed in the volcano area, as well as by officials in field mission in the area of influence of the volcanic structure.

Pulse of tremor at 4:33 p.m. were associated with observed emission of ash from the east and west of the volcano. This seismicity related to fluid circulation is mainly located in the Arenas crater and around it . The above mentioned processes are usually accompanied by thermal anomalies (another typical feature of active volcanoes) which can be monitored using satellite images provided by different organizations such as Mírová portal from Italian universities of Turin and Florence. The September 26, 2015, a large thermal anomaly in the vicinity of Arenas Crater confirming the instability of the volcano Nevado del Ruiz corroborated that the eruptive process continues to evolve.



Seismic activity associated with the fracturing of the rock in the volcanic structure is located near the Arenas crater and to the north of it, at depths between 7.5 and 1.3 kilometers. The maximum recorded was magnitude M1,1 (local magnitude), corresponding to an earthquake on September 22 at 10:27 (local time) at a depth of 4.0 kilometers, this earthquake was the most energetic of the last week. Continuous volcanic deformation show some changes.

The volcano continues to emit into the atmosphere of significant amounts of water vapor and gases, including sulfur dioxide (SO2). The column of gas, steam and ash reached a height of 2000 meters above the summit of the volcano. The direction of the dispersion of the column was in harmony with the wind regime, which remained mostly to north-west of the volcano.

The Colombian Geological Service through the Volcanological and Seismological Observatory of Manizales continued to lead the process of socialization of technical information with various stakeholders in risk management in the departments of Tolima and Caldas.

The Colombian Geological Survey wishes to clarify that the different stations that are part of the network segment of volcanic surveillance in northern Colombia, within which lies the Nevado del Ruiz volcano are fully operational. In recent months, has been considerably improved the existing instrumentation with the installation of new stations focused on the diagnosis of the activity of the monitored volcanoes.

While the volcano Nevado del Ruiz remains to this day a yellow level of activity, it is possible that additional changes occur in the behavior of volcanic activity, indicating greater system instability and may involve changes in activity level.

Source : SGC ( http://www2.sgc.gov.co/Manizales/Publicaciones/Reportes-de-actividad/Reportes-semanales/)

Photo : SGC ( 2012)



Kilauea, Hawai :

19 ° 25’16 « N 155 ° 17’13 » W,
Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE

Activity Summary:

Kilauea Volcano continues to erupt at the Overlook Vent within its summit caldera and at Pu’u ‘O’o in its East Rift Zone, showing no significant changes. The inflationary stage of a summit DI event has begun, following a small net deflationary tilt measured since the DI onset on October 1. Seismicity, deformation, and outgassing continue at low background rates across the volcano. No significant local seismic events are noted. There is no lava flow threat to nearby communities.


This wide view shows the lava lake active within the Overlook crater, which is set within the larger Halema’uma’u Crater. There have been no major changes in the lake in recent weeks. This morning the lava lake was roughly 60 meters (200 feet) below the rim of the Overlook crater. The dark region surrounding the Overlook crater is lava that spilled out onto the floor of Halema’uma’u Crater in April and May of this year, when the lake level was much higher.

Summit Observations:

At roughly 1730h October 2 Hst, Kilauea summit tiltmeters reversed and began to record the inflationary stage of the summit DI cycle that started on October 1. Since this turnaround in measured tilt, roughly 1 microradian has been recovered of the net 1.5 microradian deflation recorded since the onset of the DI. Webcam views of the lava lake within the Overlook Vent show a rise in lava lake level since yesterday’s lake-level measurement of 66.5 m (roughly 218 feet) below the present floor of Halema’uma’u Crater. Low levels of seismic activity continue. Volcanic tremor amplitudes vary in association with changes in lava lake level, circulation and spattering. The summit sulfur dioxide emission rate ranged from 1,500 to 4,300 metric tons per day during the 2-week period ending September 30.


October 1, 2015, 7am – Pu’u ‘O’o overflight: Stiff winds flattened the gas plume rising out of the crater. USGS instrumentation sits along the edge, allowing the geologists to gather the all important information on activity within.


Pu’u ‘O’o Observations:

No significant changes in tilt or eruptive activity are noted at Pu’u ‘O’o. Tiltmeters at Pu’u ‘O’o show a small deflation, possibly associated with the summit DI in progress. Sulfur dioxide emission rate from all East Rift Zone vents was about 400 metric tons per day when measurements were last possible on September 14, 2015.
June 27th Lava Flow Observations:
The ‘June 27th’ lava flow continues with scattered surface flow activity. An updated (2015-09-30) map of the flow field shows all activity to be within 7 km (4.3 mi) northeast of Pu’u ‘O’o. The overall level of surface activity appears to have declined slightly compared to the past few months. The lava flow is not threatening any communities.
Source : HVO
Photo : HVO, Bruce Omori .

Krakatau, Indonésie :

Back from Indonesia,

where I could approach the volcano of the Sunda Strait , I give you these little comments.First, I was impressed by its growth. I let you compare the two photos below, taken at approximately the same place by boat.The first, taken in 2001,

The second, in September 2015:

Then the impression that remains is that the volcano has lost it’s Anak’ … I had the feeling that it is no longer Anak Krakatau, the son of Krakatau, but rather a healthy volcano adult with formidable appearance.

The degassing from the summit was not very violent, but with some bluish color (magmatic gases). And impacts of bombs in breadcrust amount on its flanks are sometimes enormous, more than two meters in diameter.

Finally, sulfur deposits are important at the top and extended.
That’s what I can say quickly. Krakatau showed me his presence, but again, what changes.

Source et photos : G Vitton
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