Quiet Week in Volcano World

This week has been so far pretty quiet as far as new or interesting geological events, but a few have occurred.

Indonesia suffered a 7.3 Mag Quake off the coast of Sumatra, prompting the government to issue a brief tsunami warning (even though the Pacific Tsunami Center stated that there was no tsunami... I'd be freaked out if I were them too!). The quake did not damage any buildings.

Chile's Callaqui volcano appears to have either never erupted as reported, or had a very brief, non-explosive event. It is now thought that the volcano was merely exhibiting vigorous fumerole steaming.

El Hierro is in a holding pattern, with tremor at a medium level, and the stain on the ocean surface persistent. Not a lot has changed since the last post.

The quake swarm that was occurring at Mono Lake in California appears to have subsided or ceased. If this was magma dike intrusion, it was a very small one.

The quake swarm at Sierraville, CA (which scientists do say is a magma dike intrusion event) is ongoing after taking a few weeks off.

The volcano Sakura-Jima in Japan broke its previous record for the most explosive eruptions in a year -- around 980! (This is one of Japan's most active volcanoes).

Jebel-Zubair off the Yemen coast is still erupting and building more land, however the eruption (at last glance) appears to be subsiding. Based on the size of the other islands in the area, it is reasonable to assume this will be a short eruption, with a lasting island (given the lava composition).

If anything new or interesting occurs, I will surely post about it! There has not been a brand-new eruption to report on so far this year, so I will update some other volcanoes I am monitoring. Stay tuned!

Yet More Continuing Quakes At Mono Lake Swarm Region

About a week went by with no quake activity at Mono Lake, CA, until yesterday 12/20, when p to five tremblors hit the region East of the Mono Lake shoreline. These quakes registered from 1.2-2.6 in magnitude at a depth of 5.1km - 8km below the surface (which is still quite shallow geologically). The ongoing swarm has still not yet been analyzed by USGS, so speculation is still an unwise idea at this time, however I'm going to take a wild guess and say that this is probably hydromagmatic, or related to a small dike intrusion... again this is speculation.

There are many possibilities as to what is occurring in this region, ranging from subterranian hydrothermal activity, tectonic stress, magmatic dike intrusion (similar to what just occurred in the Sierraville, CA region), or other anomalies. The most recent eruptive activity occurred at Mono Lake less than 200 years ago (as per argon dating), which resulted in the extrusion of a rhylotic cryptodome. So given this (geologically) recent activity, it is probably safe to assume that these quakes are not purely tectonic in nature.

Indeed Mono Lake is considered by some to be a part of the Long Valley Caldera region, although most scientists say that they are chemically and magmatically distinct from each other. This could be the case, but they do share similar geologies, and are along the same fault area, so they could have a few things in common. I have posted more screenshots of the most recent additions to the quake swarm (Screenshots are of Google Earth with the USGS real-time Earthquake layer added). The quakes from the start of the swarm no longer appear on this screenshot as they are more than 1 week old. This screenshot only displays the quakes within the past week.

The below screenshot is some of the wave forms recorded (I am no geologist, but if one of my readers happens to be, please feel free to comment on the wave forms in all your scientific glory). This waveform is from the 2.6 magnitude quake (below picture from USGS at this link ).

                               

While I am no expert on seismic waves, these no not appear to be harmonic tremors, but I could be mistaken. These simply look like common rock-breaking quakes to my eye, which could mean these are purely tectonic. Again, I'd really like an actual expert on wave forms to weigh in on this, but my Internet exposure is still in its infancy as far as this blog is concerned. However I am the only person (to my knowledge) reporting on these quakes at this time, so hopefully someone with the correct qualifications will run across this post.

I have reviewed some past wave forms of tectonic quakes that occurred near this ares earlier this year (located here) and they are quite similar to the wave forms in the above snapshot.

This swarm is still very intriguing, mostly because of how localized (within only a couple miles) these quakes are occurring. It certainly begs the question, will we be seeing minor activity at Mono Lake in the near future? I will be keeping my eye on this for a while, or until the situation stops.


****UPDATE****
12/24/2011

There were two quakes today at the swarm region registering 2.0 and 2.7 at a depth of 3.7 miles. These quakes are a bit stronger than the typical ones so far. Keeping an eye on the continuing swarm. It is hard to tell given the local clustering of these quakes whether or not this is purely tectonic... the quakes could certainly indicate minor dike intrusion.

Continuing Earthquake Activity At Mono Lake

Mono Lake quake swarm continues. As of this writing there have been now more than 40 localized quakes SE of the lake, concentrated in a 2 mile cluster on the surface, with most quakes occurring at a depth of approximately 5-6km. This so far has still not been reviewed or analyzed by any USGS authority that I am aware of. It is entirely possible that they consider this to be routine activity. I would however be pleased to see an analysis whether or not there is any harmonic tremor, or if these quakes are in any way volcanic in nature.

The last eruptions of Mono Lake occurred a 'mere' couple hundred years ago, when a  rhyolitic cryptodome uplifted parts of the lake, and created the famed tufa towers along the lake rim. There are tens of volcanic cones and other volcanic features in the area, which is also close, but not related to, the Long Valley Caldera. Other quake swarms have occurred further to the ESE or the Mono Lake Swarm, and this raises the question as to whether or not these quakes are preceding a minor eruption in the area.

Time will tell. This could be purely tectonic, but judging by the locations and depths of these quakes, it is my opinion that this ought to be looked at by geologists and an analysis should be made public. I will continue to monitor the situation.

As requests (in comments below) come in as to what tool I am using to monitor the quakes, I have provided links to the very USGS plugin I use for Google Earth. I find it extremely useful.

In any case, here is a screenshot of the latest data that the KML file provides. Data is updated every 5 minutes, with earthquakes in the last hour appearing as red, the last 24 hours as orange, and the last week as yellow. Clicking on each dot will being up the details of the quake, with links to the official USGS analysis.

Enjoy the screenshots!

                            

Alaska's Gareloi Volcano Showing Harmonic Tremor

Alaska's Gareloi volcano, in the Aleutian Islands, appears to be displaying strong harmonic tremor. AVO states "Seismic station GAEA is 3.3 km (2.0 miles) from the summit of Mount Gareloi", so this does appear to be directly monitoring the volcano. Note the increasing strength of the tremor, similar to the tremor recently observed at El Hierro in the Canary Islands during its current eruptive phase. (Image Below)

Gareloi is a very remote volcano on the SE of the Bering Sea, and thus visual reports from the area are few and far between. It is indeed possible that volcanoes regularly erupt in this area without anyone noticing due to inclement weather, and sparse population. The recent eruption/lava dome extrusion that occurred on Cleveland volcano this past few months was only observed through satellite photos, which are expensive to schedule, so it would not surprise me in the very least if AVO never confirms an eruption at Gareloi (although you can email them, and they do usually respond, which is nice).

Gareloi is one of the Aleutian Islands most active volcanoes, having had several historical eruptions. Below is information from Smithsonian GVP:

"The 8 x 10 km diameter Gareloi Island, the northernmost volcano of the Delarof Group at the western end of the Andreanof Islands, consists of a stratovolcano with two summits and a SE-trending fissure. This prominent fissure was formed during an eruption in 1929 and extends from the southern summit to the sea. Steep sea cliffs that are cut into rocks of an older, eroded center are found on the SW coast. Young lava flows cover the older volcano from the 1573-m-high summit of Gareloi to the coast along three broad axes trending NW, ENE, and south. The 1929 eruption originated from 13 craters along a 4-km-long fissure. Phreatic explosions were followed by the ejection of glassy pumice, lapilli, scoria, and older blocks, as well as by the emission of four short, steep lava flows, one of which reached the SE coast."

Indonesia's Mount Gamalama Erupts, Closing Airports

Another of Indonesia's volcanoes erupted today, causing airports to shut down near Halmahera. Mount Gamalama sent clouds of gray ash high into the air, while locals reported seeing lava descent from the summit down the volcano's flanks. The last major eruption of Gamalama was in 2003, and had similar affects on the local population.

From Smithsonian GVP:

Gamalama (Peak of Ternate) is a near-conical stratovolcano that comprises the entire island of Ternate off the western coast of Halmahera and is one of Indonesia's most active volcanoes. The island of Ternate was a major regional center in the Portuguese and Dutch spice trade for several centuries, which contributed to the thorough documentation of Gamalama's historical activity. Three cones, progressively younger to the north, form the summit of Gamalama, which reaches 1715 m. Several maars and vents define a rift zone, parallel to the Halmahera island arc, that cuts the volcano. Eruptions, recorded frequently since the 16th century, typically originated from the summit craters, although flank eruptions have occurred in 1763, 1770, 1775, and 1962-63.

New Activity in Grímsvötn Volcano, Iceland

Several sources are reporting harmonic tremor at Grímsvötn volcano in Iceland. Grímsvötn volcano had its largest eruption in 140 years just months ago in May of 2011, which was approximately 10 times the size of the eruption at Eyjafjallajökull in 2010. The eruption at Grímsvötn however fell upon favorable winds for Europe, and did not cause the same amount of airway chaos as the 2010 eruption.

Reports thus far are that the tremor in Grímsvötn is much higher and stronger than the tremor that led up to its last eruption. This however does not mean that an eruption is imminent, or going to occur for sure. Harmonic tremor does typically indicate magma movement, but it could also be hydrothermal. In any case, the tremor could merely mean that the magma chamber is beginning to inflate again, and this could stop at any time if the pressure is right.

Grímsvötn is one of Iceland's most active volcanoes, and also one of the largest. Its remote location in the middle of the Grimsfjall glacier, the largest in Iceland, makes it a relatively safe volcano, all things considered. It has however had massive eruptions that in the past have discharged incredible amounts of glacial melt water into the ocean. The last eruption, though powerful, did not last long enough to melt a significant portion of the glacier, though floods did occur.

More Quakes Added To Mono Lake Quake Swarm

At this time, the quakes in the initial Mono Lake swarm have reached over 15 shallow tremors East of the lake. No news from geologists as of yet on this, however the quakes do seem to be getting deeper, not shallower, which could be a good thing volcanically speaking... or not. There are a couple possibilities.

One possibility is that surface activity regarding the quakes is sending tectonic tension downward, eventually causing lower and lower depth quakes, with some upper region quakes accompanying that activity. The second possibility is that the surface tension has been broken, allowing for magma intrusion from a lower depth. As far as I know, that's the only reason for a shallow initial swarm, with lower depth tremors following. The only other explanation is that these quakes are possibly precursors to a larger one, or that these are simply tectonic in nature.

In any case, since nobody is really covering this yet, I'm keeping my eye on it. I highly doubt this has the possibility to lead to an eruption, but as the saying goes, speculation is useless. 

Growing Fears About Katla Eruption (And Why You Should Pay No Attention)

Previously I've written about Katla, Iceland's large volcano capped by a glacier, next door to the now infamous Eyjafjallajokull volcano. In that article I mentioned that Katla is a ticking time bomb, and an eruption from Katla would likely be devastating economically, and possibly physically, as molten lava crashes into glacial ice causing immense explosions. However I did state in that article that "attempting to predict when an eruption will happen is a waste of time, as is proven time and again."

The News Media in the UK does not seem to understand this. An article released by the BBC today has a lot of great facts about Katla, but injected a silly notion into the article that "An eruption is imminent" or "long overdue".... I'm sorry, I didn't know we were on the BBC's schedule when it came to volcanoes erupting... I was under the impression that volcanoes erupt when conditions are right, conditions that only the volcano knows.

So I want to be QUITE clear about this. Katla WILL LIKELY ERUPT in the future, but it is IMPOSSIBLE to say when. Like I said in a previous post, it could be a matter of hours, days, weeks, months, or even years, decades, or centuries. Heck, it might not even blow up at all, and simply seethe as other volcanoes of the world do. The point is, trying to play up the possibility of a massive eruption by calling it "Imminent" or "Overdue" is presumptuous and damaging to good science.

In any case, here is the real info on Katla. Yes, it may have had a minor eruption this year which caused a glacier outburst flood and damaged some roads and a bridge. Yes, Katla has indeed had over 500 earthquakes in the last month within the caldera. And yes, historically speaking, we should be aware of Katla after an eruption from Eyjafjoll... but these are all merely indicators that "the volcano is active, and not dead", and it does not mean that a volcano eruption is "Imminent" or "Overdue". The same thing could be said about Yellowstone Volcano, that it breathes in and out, has active geysers, and many many swarms of earthquakes... yet it has not erupted in our lifetime, or in historical time.

So before you go getting all panicky about an eruption from Katla, just remember who you're reading about the volcano from. The BBC, much like any news organization, is out to make money, not promote sound science. The more people they can get worrying about a supposed doomsday scenario, the more bad press they sell. Iceland is furious about the bad coverage about Katla, and is trying its best to get the truth out, so I will help them.

So to recap, yep, Katla isn't dead, it is an active volcano. That's the only fact you'll find that you can stake your reputation on. Other than that, yeah, its a dangerous volcano and probably will erupt. Saying when, again, is STUPID, unscientific, and foolish. Let's just say, I personally would not go hiking to the summit any time soon. Other than that, don't lose any sleep over Katla if you don't live in Iceland... and even if you do, you're probably fine.

Small Quake Swarm At Mono Lake Volcano (California)

Mono Craters, California
12/1/2011

A series of small quakes ranging from magnitude 1.9 to 2.5 occurred and is ongoing today just east of the shore of Mono Lake. The quakes were relatively shallow, from 5km underground to less than a quarter mile. The quakes were clustered in a somewhat linear direction, making it very possible this is just tectonic stress, but as is the case for most volcanoes, there is always the possibility for magma movement. The events have not undergone review as of yet by scientists, so speculation about the quakes is useless. A picture is posted below:

The Mono Lake, and surrounding Inyo Craters/Mammoth Mountain/Long Valley area are all volcanic areas and small quakes here are quite common. Every once in a while there is a scare in the area when it comes to the specter of an eruption. In the early 90's, tree kill occurred at Mammoth Mountain, and caused at least one fatality due to the inhalation of CO2 gases released from the ground. This was thought by scientists to be related to dike intrusion under Mammoth Mountain.

Mono Lake has had at lest one eruption in historical time, the last being somewhere between 100, and 250 years BP (Before Present). During this eruption, a rhyolitic cryptodome grew underneath the lake, resulting in the formation of spectacular "Tufa Towers" that stand around the rim of the lake like gigantic garden gnomes. The water in the lake is high in arsenic, and it was recently discovered that certain microbes in the water actually feed on and process arsenic, much to the amazement of biologists. This of course bolsters NASA's stance that where life can exist, it will.

At present nobody has raised the alert level at Mono Lake or sounded any alarms, so there is most likely no risk of any sort of eruption at this time. However the swarm just started today and it's probably worth keeping an eye on, as this area is home to some pretty large volcanoes. As of this morning, this concentrated area of earthquake activity has recorded about 8 tremors, which have all occurred within a few hours of themselves, with another one just having occurred as I am writing this.

From Smithsonian GVP:


"The Mono Lake volcanic field east of Yosemite National Park and north of the Mono Craters consists of vents within Mono Lake and on its north shore. The most topographically prominent feature, Black Point, is an initially sublacustral basaltic cone that rises above the NW shore and was formed about 13,300 years ago when Mono Lake was higher. Holocene rhyodacitic lava domes and flows form Negit and parts of Paoha islands off the northern shore and center of the lake, respectively. The most recent eruptive activity in the Long Valley to Mono Lake region took place 100-230 years ago, when lake-bottom sediments forming much of Paoha Island were uplifted by intrusion of a rhyolitic cryptodome (Stine, in Bailey et al. 1989). Spectacular tufa towers line the shores of Mono Lake."