Thursday, November 22, 2012

Italy Volcano Stromboli Has Large Eruption

Italy's volcanic island of Stromboli put on quite a show today, as a large plume of gas and ash reached up to 3km above the summit. No damage was reported. Stromboli is one of the most active volcanoes in Italy, second probably only to Mt. Etna which is near constantly active. This eruption type is uncharacteristic of Stromboli, which is known for "Strombolian Eruptions", which, obviously, is the source of the term. Strobolian eruptions are characterized as small to medium sized eruptions in which red hot ejecta is discharged from the summit of the volcano, typically making quite a spectacular, and relatively safe show.

A statement on Facebook from INVOLCAN (which also monitors some other European and North African volcanoes) said (translated from Spanish)

"LAST minute: Strong explosions in one of the most famous volcanoes of the planet, Stromboli. There is no damage, although the column reached 3 km above the volcano, very unusual thing in this well-known Italian volcano." 



Photo: Giovanni Simonelli

Stromboli is characterized by the Smithsonian USGS:

"Spectacular incandescent nighttime explosions at Stromboli volcano have long attracted visitors to the "Lighthouse of the Mediterranean." Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout much of historical time. The small, 924-m-high island of Stromboli is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The Neostromboli eruptive period from about 13,000 to 5000 years ago was followed by formation of the modern Stromboli edifice. The active summit vents are located at the head of the Sciara del Fuoco, a prominent horseshoe-shaped scarp formed about 5000 years ago as a result of the most recent of a series of slope failures that extend to below sea level. The modern volcano has been constructed within this scarp, which funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild strombolian explosions, sometimes accompanied by lava flows, have been recorded at Stromboli for more than a millennium."

Sunday, November 11, 2012

6.8 Mag Earthquake Strikes Myanmar

A 6.8 magnitude quake struck Myanmar today near the volcanic Singu Plateau, a trachyandesitic lava field fed by fissures near the fault line in question.  So far 13 people have been confirmed dead. The epicenter of the quake was about 15-20 miles NNW of the volcanic center, and multiple aftershocks of 5.0-5.8 have now occurred at the volcanic center, less than 2 miles away at depths of about 10km.



Screenshot of Google Earth with USGS real-time quake overlay.

The quake occurs as newly re-elected US President Barack Obama is scheduled (in about a week) to arrive in the war-torn nation formerly known as Burma for talks with their newly elected president Aung San Suu Kyi in regards to helping the fledgling democracy improve their country and better interact with the international community.

It is unclear at this time whether this quake will spur any activity at the Singu Plateau, but as it has not erupted for several millenia, it is probably not likely, although it is remotely possible. The Singu Plateau is not a closely stidied volcanic system. It exists on the fault line that extends South through the region, and consists of fissure vents that tend to send lave West of the vents. It is not clear the last time it had an eruption, although the Smithsonian Global Volcanism Program characterizes the Singu Plateau as Holocene in age:


"The Singu Plateau volcanic field, also known as Letha Taung, is a Holocene basaltic trachyandesite lava plateau in north-central Burma, north of the city of Mandalay. The lava flows originated from fissure vents and cover an area of about 62 sq km"

No age is given for the last eruption.

A post from volcanologist John Seach is quoted as saying:

"A magnitude 6.6 Earthquake hit 36 km north of Singu volcano, Burma on 11th November 2012. Two magnitude 5.0 aftershocks occurred 8 and 13 km from the volcano two hours later. The last eruption at Singu volcano is unknown but probably occurred in the past 10,000 years, which makes it an active volcano on a geological timescale."

As of now there have only been 4 major aftershocks, a 5.8, a 5.6, and two 5.0 quakes. Three of these have occurred within the volcanic region.


Wednesday, November 7, 2012

Magnitude 7.4 Quake Strikes Guatemala

A Magnitude 7.4 earthquake has just struck off of the coast of Guatemala in another Pacific subduction quake. There were no immediate reports of damage, and the inland appears to have been spared major shaking due to the mountain ranges that seem to have served as a buffer. The quake occurred off of Guatemala's west coast at a depth of 41.6km, which is also why the surface intensity must have felt a bit lower (shallower quakes are typically a lot more damaging).


Google Earth snapshot with USGS real time quake plugin.


There are no immediate detailed reports for this quake. A blog on CNN is the most up-to-date at this time. There was no threat of a tsunami according to the Pacific Tsunami Warning Center, who's statement is below:

"TSUNAMI INFORMATION STATEMENT NUMBER 1
NWS PACIFIC TSUNAMI WARNING CENTER
EWA BEACH HI 643 AM HST WED NOV 07 2012
TO - CIVIL DEFENSE IN THE STATE OF HAWAII SUBJECT - TSUNAMI INFORMATION STATEMENT
THIS STATEMENT IS FOR INFORMATION ONLY.
NO ACTION REQUIRED.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS ORIGIN TIME - 0636 AM HST 07 NOV 2012 COORDINATES - 14.0 NORTH 92.2 WEST LOCATION - OFF THE COAST OF CHIAPAS MEXICO MAGNITUDE - 7.5 MOMENT EVALUATION

BASED ON ALL AVAILABLE DATA A DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS NOT EXPECTED AND THERE IS NO TSUNAMI THREAT TO HAWAII. REPEAT.

A DESTRUCTIVE PACIFIC-WIDE TSUNAMI IS NOT EXPECTED AND THERE IS NO TSUNAMI THREAT TO HAWAII. THIS WILL BE THE ONLY STATEMENT ISSUED FOR THIS EVENT UNLESS ADDITIONAL DATA ARE RECEIVED. "

There are many volcanoes int he area, as this epicenter lies along the so-called Pacific Ring of Fire. Volcanoes in the area include (from NW to SE):

Tacaná
Tajumulco
Santa Maria (currently erupting)
Almolonga
Santo Tomás
Tolimán
Atitlán
Fuego
Acatenango

Quakes of this magnitude can affect seismicity in active volcanoes, especially ones that frequently erupt, or have a very pressurized magma chamber. It is unclear at this time whether or not this will be the case.