30/04/2015. Kilauea , Piton de la Fournaise , Ruapehu , Dempo .
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
KILAUEA INFORMATION STATEMENT
After a week of elevated activity, HVO would like to review recent observations and thoughts on what we may expect next at K?lauea Volcano.
LAVA FLOWS ON THE FLOOR OF HALEMA?UMA?U
Beginning at about 9:40 p.m., HST, last night and continuing into this morning, the Overlook crater lava lake overflowed its rim on several occasions, sending short, lobate sheets of pahoehoe as far as 130 m (142 yds) across the floor of Halema’uma’u Crater. These overflows were captured on USGS-HVO’s web cameras. Thus far, the flows have been brief and their forward motion ceased as the lava lake level fell and lava subsided into the Overlook crater. As yet, no change in lava spattering or surface circulation patterns on the lake in response to these overflows has been noted.
An early morning view of the lava lake with a recent overflow onto the floor of Halema’uma’u Crater.
Given the sustained high, and slowly rising, levels of lava within the vent during the past week, these overflows were expected and they are likely to continue intermittently. During similar lava lake activity at Halema?uma?u in the 1800s and early 1900s, lava lakes frequently produced overflows. Over time, overflows and intermittent spattering can build a collar of solidified lava that then contains the rising and circulating lava lake. This phenomenon is known as a ‘perched lava lake.’
ROCKFALLS, EXPLOSIONS, AND SPATTER ON THE HALEMA’UMA’U CRATER RIM;
ASHFALL AT JAGGAR OVERLOOK AND BEYOND
Yesterday morning at about 10:20 a.m., HST, a rockfall from the southeast wall of Halema’uma’u Crater above the lava lake initiated an explosion from the lake surface. Large clots of molten spatter up to 2 meters (2 yards) across showered the rim of Halema’uma’u in the vicinity of the closed visitor overlook fence. The hot spatter formed a nearly continuous blanket for about 100 m (110 yards) along the crater rim and extended back from the rim about 50 m (55 yards). Small bits of crater-wall rock were embedded in the spatter clots.
Photo from the rim of Halema’uma’u showing the lava lake in the completely filled Overlook crater. Repeated overflows are beginning to construct levees around the lake, such that the level of the lake is now perched about 2 m (7 ft) above the original floor of Halema’uma’u.
Visitors to the Hawai’i Volcanoes National Park Jaggar Museum Overlook and other Park areas should also note that under southerly wind conditions, similar rockfalls and explosions can result in a dusting of powdery to gritty ash composed of volcanic glass and rock fragments. Several such ashfalls occurred last weekend and, although they represent a very minor hazard at this time, people should be aware that additional dustings of ash are likely at Jaggar Museum and other areas around the Kilauea summit.
CONTINUED INFLATION AND EARTHQUAKE ACTIVITY IN THE KILAUEA SUMMIT AND UPPER EAST RIFT ZONE
For the past week or so, HVO monitoring networks have recorded steady inflation of the K?lauea Volcano summit area. Shallow earthquake activity has also been elevated beneath the summit caldera, upper East Rift Zone, and upper Southwest Rift Zone. Of the hundreds of earthquakes that have occurred in the past week, most have been small, less than magnitude-2 (M2).However, this morning (April 29) a M3.0 earthquake occurred at the easternmost caldera boundary. It is the second M3+ earthquake in this region during this sequence.
Spatter from the explosion also landed on the Halema’uma’u webcam, melting some of the wire insulation but not enough to interrupt its operation.
During this period of elevated summit activity, there has been no obvious change in the eruption rate of lava from Pu’u ‘O’o. Rates of gas emission from both the summit and Pu’u ‘O’o remain largely unchanged. Short-lived increases in sulfur dioxide from the summit lava lake have been noted during rockfall-triggered explosive events, such as the one that occurred yesterday morning.
Source : HVO
Piton de la Fournaise , La Réunion :
Communiqué of OVPF from Wednesday, April 29, 2015 at 16:30.
Review of the activities of the day.
Highlights since 4:00 this morning The OVPF having recorded an increase in activity under the Piton de la Fournaise suggested the change to the level of alert. Prefecture of Réunion decided to switch to Alert 1 (probable eruption) at 6:00 this morning.
For the day of April 29 between 0:00 and 12:30 TU (between 4:00 local and 16.30), the networks have recorded:
57 volcano-tectonic earthquakes summital (either by extrapolating more than 100 per 24 hours).
8 deep volcano-tectonic earthquakes.
Flow constant of magmatic gases.
Piton de La Fournaise – Déformations enregistrées au sommet du volcan entre le 13 et le 28.04.2015 – Doc. OVPF
Deformation recorded at the top of the volcano between 13 and 28.04.2015 – Doc. OVPF
8 deep earthquakes registered are the first observed since Saturday April 25th. The OVPF team went to the Pas de Bellecombe and repeated measurements of CO2 in the soil. These measurements show a marked increase in the flow of the released gas deeply. This increase of CO2 measured at the surface is in line with the recording of deep earthquakes.
Source : OVPF
Photo : OVPF (2006)
Ruapehu , Nouvelle Zélande :
GNS Science warns that intermittent tremors from Mount Ruapehu are at a level not seen since the eruption of 2006 and the 2007 lahars. Volcanic tremors from Mount Ruapehu over the past 2-3 weeks have been “moderate to strong”, said the GNS in a press release and they were among the strongest measured during the last eight years.
“The signals are similar to those of 2006 and 2007, but lower than those recorded in 1994-1995.” The GNS warned that, historically, a direct relationship between earthquakes and volcanic eruptions has not been established, but that was a signal often present before, during or after an increased volcanic unrest.
Mt Ruapehu remains at the level of volcanic alert 1 (minor problems) on a scale from 0 to 5, and GNS Science continues to closely monitor the volcano through the GeoNet.
The eruption in 2006 sent a plume of water 200 meters into the air with waves up to 6m hitting the walls of the crater lake. The 2007 lahar occurred after the wall from crater lake composed of volcanic material has yielded, releasing about 1.4 million cubic meters of mud, rocks and water in the Whangaehu River.
No one was injured but the roads were closed and a property was cut after the lahar has destroyed its access road.
A spectacular eruption in 1995 had sent a huge plume of ash into the air and the crater lake had been emptied, travel in air was disturbed and surrounding areas covered with volcanic ash.
Source : GNS
Dempo, Indonésie :
Visual observations from G. Dempo made from PGA station of Dempo, April 27, 2015 show constantly smoke gusts. The seismic data recorded by the station Vulknaik Dalam (VA) in the period 1 to 29 April 2015 at 12:00, showed an improvement compared to previous months data. A phreatic eruption in the form of rain of ash and sludge can occur suddenly and fall within 1 km from the eruption center.
An increase in the activity of G. Dempo, visually represented in the seismic data is recorded. With conditions mentioned above, the level of activity from G. Dempo rise from level I (normal) to level II (Waspada) from the date of April 29, 2015 at 16.00 pm. Public order asking tourists not to approach the crater lake Marapi of G.Dempo within 1 km, to prevent a rash from the central crater and volcanic gases that can be harmful to life.
Source : VSI
Photo : vulkaner.no