Volcano watch

[Sevan Makaracı]

Japan: A new island appears in the Ogasawara Islands - November 2013

Active volcanoes (Sep 28, 2012)

Source

Source

"Of course all volcanoes will explode, as this is going to be a very severe pole shift. What about the months and years preceding the pole shift? It is no secret that Mammoth Lake and the caldera of Yellowstone are warming up, and the populace has been prepared for these occurrences by the movie Volcano where there, in the middle of LA, lava is bubbling up. In fact, there is a fault line running from the approximate San Diego/LA area, up into the Sierras, and this is liable to rupture rather violently during one of the quakes that precedes the pole shift by some months. Volcanic eruptions from that area in the Sierras can be expected. Will Mount St. Helen erupt? All volcanoes that have been active within the memory of man will begin spewing and burping and oozing, and many that were not expected to become active will reactive. "   ZetaTalk - Feb 15, 2000

[Sevan Makaracı]

SEP 6 :

Seismic activity; Campi Flegrei caldera, W.Naples/Italy

 

http://hisz.rsoe.hu/alertmap/read/index.php?pageid=svolcano_index&a...

[Sevan Makaracı]

SEP 6 :

Increased seismicity at Iceland's Katla has finally begun to show up in the mainstream media : Iceland volcano sees surge in seismic activity

 

A surge of small earthquakes has been reported around Iceland's Katla volcano, but scientists said Tuesday there is no immediate concern that the increased seismic activity will trigger a dangerous eruption.

Although earthquakes around Katla are common, an increase in cluster earthquakes is not.

"It's one of the most feared volcanos, so we're closely monitoring it," said Pall Einarsson of the University of Iceland. "That said, it's normal for earthquakes to be detected around Katla. What's a bit unusual is that we're seeing swarms of small earthquakes, some occurring every 10 minutes or so."

Iceland sits on a large volcanic hot spot in the Atlantic's mid-oceanic ridge. Eruptions, common throughout Iceland's history, are often triggered by seismic activity when the Earth's plates move and when magma from deep underground pushes its way to the surface.

Like earthquakes, predicting the timing of volcanic eruptions is an imprecise science.

Last year's eruption of the Eyjafjallajokull volcano forced hundreds of people to be evacuated and paralyzed international air travel for weeks because of a hovering ash cloud.

And history has shown that when Eyjafjallajokull volcano erupts, Katla — located under the massive Myrdalsjokull icecap — isn't far behind.

Katla, which threatens disastrous flooding if its ice cap melts, typically awakens every 80 years or so, and last erupted in 1918.

Activity around Katla started to increase around July but has since grown even stronger. The strongest earthquake detected so far has been a 3.0 magnitude. There also was flooding that wiped out a bridge in July.

Like people, each volcano has a different personality of sorts, says Einarsson.

"We look at the behavior, try to analyze patterns and then try to come up with an explanation," says Einarsson. "This is a bit difficult to interpret so far, but it's correct to say that it signals some sort of activity in the volcano and some sort of magna intrusions are probably taking place."

Geologists also are worried about the Hekla volcano, which unlike Katla, is not covered by a glacier and produces little seismic activity.

During the Middle Ages, Icelanders called the Hekla volcano, the country's most active, the "Gateway to Hell," believing that souls were dragged into the fire below.

"If we saw earthquakes like this in Hekla, we would immediately signal a warning sign," Einarsson said.

Another one of Iceland's volcanos proved particularly deadly in 1783.

When Laki erupted, it freed gases that turned into smog. The smog floated across the jet stream, changing weather patterns. Many died from gas poisoning in the British Isles. Crop production fell in western Europe. Famine spread.

"Everyone has their eyes on a big Katla eruption," said Andy Russell with Newcastle University's Earth Surface Processes Research Group, who travels frequently to Iceland for research. "You can never say never, but I don't think there's need for alarm right now."

Russell said past Katla eruptions have caused floods the size of the Amazon and sent boulders as big as houses tumbling down valleys and roads. Flooding occurred within 45 minutes of the eruption, he said.

Iceland is one of the few places in the world where a mid-ocean ridge actually rises above sea level. Many volcanic eruptions along the ocean basin often go undetected because they can't be easily seen.

http://www.msnbc.msn.com/id/44410235/ns/technology_and_science-scie...

http://www.cbsnews.com/stories/2011/09/06/ap/europe/main20101974.shtml

[Sevan Makaracı]

SEP 06 :

Katla seismic activity continues - Growing harmonic tremor spike in Katla volcano

 

At this moment it seems that there is a growing harmonic tremor in Katla volcano. This harmonic tremor started today after the earthquake swarm that took place earlier today. After it stopped a spikes of small harmonic tremor spikes did start to appear. During the past few hours they have been growing in size. But it seems that the harmonic tremor drops for few moments between spikes.

From what I can tell this harmonic tremor signal is growing every few hours or so. It is possible that this is a repeat of what did happen in July. But for the moment it is too early to know that for sure at the moment. But for the moment there is no eruption about to start in Katla volcano.
When I was writing this blog post, it seems that a new earthquake swarm is about to start in Katla volcano. But the earthquake swarms in Katla volcano often start slowly with few earthquakes, but they seems to grow with time.

 

Source

Growing harmonic tremor spike in Katla volcano

[Sevan Makaracı]

SEP 05 :

Seismic activity - Magnitude 6.6 eq struck N.W.of Toba supervolcano caldera

 

A strong, deep 6.6 magnitude earthquake struck just northwest of the Lake Toba super-volcano caldera, just after a 5.1 quake further south August 31st.. The epicenter of the earthquake was 100 km (62 miles) SW of Medan, Sumatra, Indonesia and 1409 km (875 miles) NW of JAKARTA, Java, Indonesia.

 

 

 

 

 

 

 

 

 

EQ details : http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0005pd...

http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0005m2...

[Sevan Makaracı]

SEP 05 :

Earthquake swarm deep on the Reykjanes Ridge


During the night a earthquake swarm started deep on the Reykjanes Ridge. This earthquake swarm is currently at distance of 730 to 735 km SW of Reykjavík. So it is clear that nobody is going to feel this earthquake swarm out in the deep ocean.

From this distance it is impossible to know if this is just a earthquake swarm or a volcano event. This distance also makes it close to impossible for the SIL network to locate this earthquakes with any details. But EMSC and USGS should show the largest earthquakes as they happen on the Reykjanes Ridge.

The largest earthquakes are appearing on my Hekla geophone, but just barely. Due to this large distance only long period seismometers are going to record those earthquakes properly.

Source

[Sevan Makaracı]

SEP 05 :

More Seismic Activity by Katla Volcano than Usual

 

The rate of seismic activity in the Katla volcano below Mýrdalsjökull glacier in south Iceland has been higher than usual with minor earthquakes regularly being picked up by sensors in the area. The last series was registered on Saturday.
“The largest earthquake was 3.2 [on the Richter scale] and an equally large earthquake hit there last Thursday,” geophysicist Einar Kjartansson at the Icelandic Meteorological Office told Morgunbladid.

“We picked up ten quakes before and after the largest one in a period of approximately 20 minutes,” Kjartansson said of the series of earthquakes on Saturday.

When asked whether this is a case of magma intrusion, Kjartansson said it is hard to tell. “We don’t know but it isn’t unlikely that it has to do with intrusions.”

He also finds it hard to predict how the activity will progress; Katla has been under observation since earthquakes started hitting there regularly. However, the most likely scenario is that the activity will gradually subdue, Kjartansson concluded.

On Saturday, the Mýrdalsjökull glacial river Múlakvísl flooded again—it tore down a bridge on the Ring Road earlier this summer—but this time the flood was not as severe and was the consequence of heavy rain rather than glacial or volcanic activity.  ESA
Photo by Geir Ólafsson

http://www.icelandreview.com/icelandreview/daily_news/More_Seismic_...

[Selim KARABIYIK]

Thank you Sevan for the timely updated information.

Katla

	Country:	Iceland
	Subregion Name:	Southern Iceland
	Volcano Number:	1702-03=
	Volcano Type:	Subglacial volcano
	Volcano Status:	Historical
	Last Known Eruption:	1918
	Summit Elevation:	1512 m	4,961 feet
	Latitude:	63.63°N	63°38'0"N
	Longitude:	19.05°W	19°3'0"W
Katla volcano, located near the southern end of Iceland's eastern volcanic zone, is hidden beneath the Myrdalsjökull icecap. The subglacial basaltic-to-rhyolitic volcano is one of Iceland's most active and is a frequent producer of damaging jökulhlaups, or glacier-outburst floods. A large 10 x 14 km subglacial caldera with a long axis in a NW-SE direction is up to 750 m deep. Its high point reaches 1380 m, and three major outlet glaciers have breached its rim. Although most historical eruptions have taken place from fissures inside the caldera, the Eldgjá fissure system, which extends about 60 km to the NE from the current ice margin towards Grímsvötn volcano, has been the source of major Holocene eruptions. An eruption from the Eldgjá fissure system about 934 AD produced a voluminous lava flow of about 18 cu km, one of the world's largest known Holocene lava flows. Katla has been the source of frequent subglacial basaltic explosive eruptions that have been among the largest tephra-producers in Iceland during historical time and has also produced numerous dacitic explosive eruptions during the Holocene.

http://www.volcano.si.edu/world/volcano.cfm?vnum=1702-03=

 

[Sevan Makaracı]

SEP 04 :

New harmonic tremors spikes in Katla volcano

 

This has become almost a daily occurrence. But today there was one harmonic tremor spike (at least) in Katla volcano. It is unclear why this harmonic tremor spikes happen in Katla volcano. But they often do happen just before a earthquake swarm starts, but often several hours before (sometimes). I am not sure why that is. But one idea is that this activity is connected to hydrothermal areas that are under the Mýrdalsjökull glacier.

 

Earthquake activity has been quiet in Katla volcano today. But it is hard to know for sure if that is going to last. As earthquake activity appears to be on the rise in Katla volcano during the whole of the year 2011 according to news in Iceland (see earlier blog post for details).
Harmonic tremor spike as seen on Lágu Hvolar SIL station. The spike is between 04/09 and 05/09. The spike is a small top in the tremor chart (hard to spot). Copyright of this picture belongs to Iceland Met Office. Harmonic tremor spike as seen on Snæbýli SIL station. The spike is between 04/09 and 05/09. The spike is the broad band that suddenly appears in the tremor data. It is easier to see then on Lágu Hvolar. Please note that it seems that Snæbýli SIL station has gone offline again, as it has stopped updating. Copyright of this picture belongs to Iceland Met Office. It is clear that Katla volcano is going for a eruption. But the question remains is just when that is going to be, but it is impossible to predict when a eruption is going to take place in Katla volcano. But the signs have come clear in my opinion in this matter. For the moment it is just waiting and watching. But this might be a long wait until something happens in Katla volcano.

Source

[Sevan Makaracı]

SEP 03 :

Another earthquake swarm in Katla volcano, 3rd swarm in 6 days :

 

Today (3. September 2011) at 16:45 UTC a earthquake swarm did start in Katla volcano. So far this earthquake swarm has been small, with the largest earthquake just with the size ML2.7 at the depth of 1.1 km (automatic data). But the quality of this earthquake was good, so location is accurate from what I can tell.

I am not sure at this moment if there is a harmonic tremor spike following this earthquake swarm or not. As the earthquakes are long period due the fact that they are created by magma movement in Katla volcano. This might be dike intrusion. But for the moment it is hard to know that for sure.

The area of earthquake activity today in Katla volcano. Copyright of this picture belongs to Iceland Met Office.

I cannot tell at the moment what is going on in Katla volcano. But the earthquakes tell me that the reason why they are happening is because of magma is moving inside Katla volcano. But latest data (not shown here) do however show that no harmonic tremor is currently ongoing, if it ever started during this earthquake swarm. I am expecting the earthquake swarm to continue and last for the next few hours. But I must point out that that is what might happen, as sometimes earthquake swarms just stop when you think that they might be about to start for real. (Source)

[Sevan Makaracı]

SEP 03 :

Inflation starts in Katla volcano :

There seems to be inflation going on in Katla volcano, at least according to the automatic GPS data that IMO has on it’s web site. But this might be error in the data. But for the moment I do not think it is. But please do look at this data with the view that it might be wrong.

 

The inflation appears clearly on Lágu Hvolar GPS station. Copyright of this image belongs to Iceland Met Office.

The inflation can be seen on Lágu Hvolar and Sólheimaheiði GPS stations. But it appears to be more clear at HVOL GPS station. But that is most likey because that GPS station is closer to the magma pocket in question that creates this movement.
The inflation also appears on Sólheimaheiði GPS station. But not as clearly as on Lágu Hvolar GPS station. Copyright of this image belongs to Iceland Met Office.

What might be the critical inflation before a eruption starts is hard to know until it happens. For Eyjafjallajökull volcano that was 60mm, for Grímsfjall volcano the inflation was actually 350mm. But that volcano had eruptions that did not change it’s inflation numbers. I do not know why Grímsfjall volcano is so different in this respect from other volcanoes in Iceland (that I know of so far).

Source

Inflation starts in Katla volcano