Shallow Quake Swarm at Joshua Tree East Of Palm Springs

There is absolutely nothing, and no information on this on the web, so I thought I might bring it into the light for scrutiny. There is a continuing quake swarm occurring in Joshua Tree National Park, about 35 miles East of Palm Springs, CA that is beginning to look quite intriguing. The range of depth is from 8km to less than 1km, and about 2 quakes are occurring every hour. The strongest quakes were two mag 3.5 tremblors that were lightly felt in Palm Springs and surrounding towns.

The area is definitely part of the Rio Grande rift, a series of spreading faults that resemble "stretch marks" on the Western USA's topography. This rift, much like the African Rift Valley (although nowhere near as active volcanically) is home to a great many volcanic features. This particular area is parallel to the San Andreas fault line, the most active fault line in the USA.

The swarm is concentrated below an ancient volcanic mountain, and has been very consistent in its locations. All quakes are occurring within a mile of each other. This does look a bit like a deep magma dike intrusion, but it is definitely still way to soon to tell what is going on. Dike intrusions into the crust happen all the time, and most times they never result in any surface volcanic activity.

A Google Earth Snapshot with USGS real-time quake overlay showing the location and number of quakes in the swarm. The largest quake occurred yesterday and was a mag. 3.5, with a matching 3.5 quake occurring today (4/4/2012).

While this probably is a magma intrusion into the crust, there are other possibilities such as these being a precursor (foreshock) to a larger quake in the future, or a very small tectonic slippage. In any case, this swarm is intriguing not just because of its location, but because of the number of quakes occurring within the area. As this is occurring along the San Andreas fault however, it is very hard to tell whether or not this is purely tectonic, or if there is an intrusion taking place.

As this is, to my knowledge, the only article about these quakes so far, I will withhold further speculation about what is going on here until (or if) the USGS comments on the quakes, or if they become newsworthy. It is simply impossible to tell from available data whether or not these events will be significant, or insignificant, but as always I will keep an eye on these interesting occurrences, and post updates if anything changes. For now, keep your eyes peeled East of Palm Springs (and I would avoid going spelunking out there any time soon!).

*****UPDATE 4/9/12*****

The quake swarm is continuing with now more than 50 quakes striking the region. The swarm is very much beginning to look like a dike intrusion, at least on the Google Earth USGS plugin. It is quite similar to the precursors at El Hierro, deep quakes, numerous, and rising in depth. Still, nobody is reporting on this, so I am at the mercy of my own assumptions, which I will keep quiet for now, but this is definitely an area to keep an eye on for a while, at least until USGS takes notice. If anything further develops, I will update this post again.

Video from El Hierro's Underwater Volcano Released

Video of the actual volcano underwater off the coast of La Restinga, El Hierro in the Canary Islands (Spain) shows a degassing and slowly erupting cone. The video, published by IGN (Institutio Geografico National) shows in very clear water, the surface of the vent degassing. It is the first video published by scientists that clearly shows what is actually happening under water, giving us our fist actual observation of the cone itself.

The eruption at El Hierro was declared over by the government, much to the chagrin of scientists and volcanologists who insist the eruption is not over, merely slow. The government is apparently quite eager to declare the eruption over as tourism has actually suffered, not prospered, during this eruption. Sensationalist news media, and negative press caused the usually booming tourist industry to slow to a crawl, and residents and businesses were forced out of the small fishing town of La Restinga, putting a large dent in their economy.

However this is a dangerous presumption for the government to make. First of all, the eruption is NOT over, and second, giving residents and tourists a false sense of security in regards to the volcano is ill advised. It is still quite possible that other vents can open up, or that activity at the main vent can resume. It is impossible to say, but in most scientists views, the eruption at El Hierro would be over as soon as there are little to no earthquakes and NO harmonic tremor.

The interesting thing about the volcano and the government is the clear attempt to cover up what is actually going on. The webcams have been shut off completely. The webcams were shut off due to "cost concerns" as the provider claimed that they were too expensive. I highly doubt that they are. This apparent "blackout" of information coincides completely with the Spanish government's declaration that El Hierro is now a "green" zone, ie: safe for tourists, boats etc. There is still a very small exclusion zone for commercial boats around the vent, but the port and town are now open.

And even as government officials claim the eruption is at an end, there was a 2.7 magnitude earthquake directly under the erupting vent, and more earthquakes in the El Golfo region (the El Golfo basin is an area that has been highly seismically active, with some scientists wondering whether or not there is another open vent at the bottom, out of reach of our instruments). So with an active and hot cone, earthquakes every day in and around the erupting vent, and now visual confirmation of the vent itself with an underwater camera... one has to ask themselves, who is the Spanish government kidding? 

Alaska's Cleveland Volcano Back To Alert Level "Orange"

AVO has again raised the alert level at Cleveland volcano due to the resurgence of yet another lava dome at the summit. Two have been emplaced slowly, and each time the dome has either exploded or collapsed in two very minor eruptions. The slowly erupting volcano has been going back and forth between "Yellow" and "Orange" aviation codes during the recent months. Typically after the dome collapses, AVO has lowered the alert level thinking that the volcano may have stopped erupting, but this has turned out not to be the case.

Cleveland volcano has been erupting for around a year, with an initial lava dome emplaced at the summit crater that reached a diameter of approximately 160M. This dome was destroyed when the volcano had an ash producing eruption. A smaller dome was extruded into the crater, and also subsequently destroyed. The current situation is another lava dome is now being built, however the current dome has not been measured.

This slowly erupting volcano can escalate the eruptive activity with little to no warning, and Cleveland was actually responsible for the only death ever from an Aleutian volcano. The "Orange" alert does not reflect the slow eruption, but its potential to enter into explosive phases at a moment's notice. The Aleutian arc is a very popular sky route for many airlines going to and from Asia to North America, and given an incident with Redoubt volcano in which a plane nearly crashed due to ash being sucked into its engines, AVO takes no chances with the safety of travelers.

For now the volcano continues to slowly seethe and push out the viscous lava into the crater, repeatedly making and destroying its lava dome. It is possible that new magma is pushing up older, cooler magma to the surface, and this is just the "cork in the bottle" so-to-speak. As AVO states, it is certainly possible for this volcano to change eruption characteristics at any moment. Good thing that this volcano is in an area of the world that is nearly uninhabited!

Earthquake Swarm and Possible Dike Intrusion at Krísuvík Volcano in Iceland

There is not a whole lot going on in the world in respect to new eruptions or volcanoes at this moment, however Iceland is always fascinating to watch. Today there was a swarm of quakes just SW of the Kleifarvatn lake, just south of the epicenter of Krísuvík volcano. The quakes were shallow, weak, and numerous, but the area is highly active, much like most of Iceland. Most of the quakes registered below a 1.0 magnitude, but were clearly seen on the many Icelandic seismic sensors. The are is home to many thermal vents, as well as hot springs, fumeroles, and fissures.

The last known eruption of Krísuvík volcano was in the 14th century (the 1500's). A few eruptions have taken place at this location after Iceland was settled, but nothing in recent times. It is probable that this swarm will not lead to an eruption any time soon, but Iceland sits on a spreading fault, so it is not a matter of if, but when this volcano will erupt again.

There are several volcanoes in Iceland that are expected to erupt at least within the next 10 years. Those are Katla, Askja, Grimsvötn (or Grimsfjall, Grimsnes), Hekla, and the Reykjanes Ridge, all of which show heightened seismic and thermal activity. However for most of these volcanoes, it is normal to display some kind of activity, and no eruption for any of these, save probably Katla and Hekla, are certain.

Icelands last major eruptions were from Eyjafjallajökull, and Grimsvötn. The Grimsvötn eruption, while spectacular to watch, was nowhere near as big a deal as the Eyjafjallajökull eruption which caused widespread economic damage due to flights to and from Europe being grounded for weeks because of the ash cloud it produced. The ash from Grimsvötn is much more coarse and larger grained than the very fine and powdery ash produced by the Eyjafjallajökull eruption, and thus fell to the earth quickly and did not get picked up by the jet stream.

The activity at Krísuvík can be attributed to a few causes. For one, Iceland is one of the worlds largest users of hydrothermal/geothermal energy, and regularly injects water into hot rocks to produce steam. This does sometimes cause swarms of quakes to occur, and it is rather hard to tell whether or not this could be related, but as the quakes happened on an active spreading fault, I suspect this is not the case, rather a small magma dike intrusion probably occurred.

Around the world most dormant volcanoes are sleeping or slowly rumbling away. Mt Etna did display some nice activity this weekend, but other than Etna's fireworks show, most active volcanoes showed relatively little activity during the month. Not good for us volcano bloggers out there to tell a story, but hey, the Earth does what it wants on its own time with little concern for my Google money! Hopefully this post is at least a good diversion! I'll post more as it occurs!

Another 6.3 Quake Hits Mexico

A magnitude 6.3 quake struck the Oaxaca region of Mexico today, near the area where the large mag 7.6 quake hit a couple weeks ago. This is the largest aftershock thus far from the 7.6 tremblor. Housing and property were damaged by the large quake, however injuries and fatalities were thankfully very low due to citizens being well prepared for evacuating. Mexico, like the West Coast of the US, is part of the Pacific Ring of Fire, an arc of subduction faults and volcanoes spanning the rim of the Pacific plate.

The quake was centered in the Western corner of the state of Oaxaca, approximately 2 miles away from the epicenter of the 7.6 quake. The quake was felt as far away as Mexico City due to the composition of the earths crust (a mix of clay sediments, and volcanic ash), which is a good conductor for seismic waves.

No volcanic unrest has been associated with these quakes. Several rumors were circulated that Popocatepetl might have been 'disturbed' by the shaking, however the volcano continues to act normally, only occasionally puffing our steam, or small amounts of ash.

Mexico is very familiar with earthquakes and volcanic eruptions. Central Mexico is home to thousands of cinder cones, vents, stratovolcanoes, and calderas. Popocatepetl is Mexico's most active volcano, having erupted fairly regularly in historical time.

The current seismicity is associated with the collision and subduction of the Pacific Plate and the North American plate, and is not volcanically related. Some quakes can and do disturb volcanoes, and can destabilize magma chambers, but most volcanoes in Mexico are long dormant, or too far from the quake epicenter to be affected in any serious way, so there is probably no risk of heightened volcanic activity as a result of the recent quakes.

*****UPDATE*****
The quake was downgraded to a 6.0 later by USGS. No reports of damage or injuries have been made apparent.