Friday, March 29, 2013

Long Running Project Nearing Completion


So, part of the reason my blog posts have been a bit sparse lately (aside from a new job with more responsibilities) is that I have been, for the last few years compiling a Google Earth database that merges the Smithsonian GVP's worldwide Holocene volcano database with my own Google Earth-browsing observations of surface volcanism on the planet Earth. This painstaking (but entirely fun) process involves me scouring the globe on Google earth for obvious volcanic vents, mountain ranges, and other volcanism, and adding place marks. I add some info about the volcanoes that I discover when I can, but many vents are either not in any database, or are in areas of the world where volcanologists have difficulty reaching.

I decided to undertake this project a couple years before I started this blog. It all started when Google Earth was just released, and I decided my first 'trip' was to look at Mt. St. Helens in 3-D. Addiction soon took hold. I found it curious that the Smithsonian only listed purported Holocene (and at the earliest, Pleistocene) volcanoes, and given that volcanoes like Chaiten, Jebel al Tair, and Nabro had woken up from slumber after tens of thousands of years of dormancy (Nabro was questioned to have been extinct before its recent eruption), I felt it would be pretty cool to compile a visual representation of all volcanoes on the planet (not including most submarine ones, but that's the next step in this obsession).

As you can see in the below screenshot, the obsession has been painstaking. Although I'm sure there are a few volcanoes I marked that aren't actually volcanoes (merely similar in shape), this has generated a really great database to look at, and I am certain I have discovered some 'forgotten' or even undiscovered volcanic vents on our planet that nobody has paid much attention to.



Screen capture of my personal volcanism database, which I will soon make available on this blog for your enjoyment.

With the advent of satellite photography, and the 3D capabilities in Google Earth, leaps in fields like Archaeology, Geology, and Volcanology have indeed occurred because of this technology. And I will be posting my database for public use (since I am not in academia, I do not particularly care for any academic credit for this, as it is just a hobby) within the next few months. I am currently just touching up some things I felt needed to be corrected, and still scouring areas of the planet where I suspect volcanism has occurred in the past, but never identified.

To be sure, the majority of the surface (if not all of it) at one time was volcanic. But I am not including ambiguous mountain ranges of the Jurassic, Triassic, or older. My database will show most 'geologically recent' meaning from Holocene back to Miocene volcanism. I want to give it out to the world of science and research in hopes that perhaps, some vents that are identified will indeed be 'discovered' by science, and perhaps even identify any lurking threats we might not have considered. My real hope is that some things that should not have been forgotten, are brought to mind and maybe monitored so that nobody gets caught by a surprise eruption. Although I am certain the scientific community, for the most part, has this well in hand.

This database could be used by teachers as an educational tool to show the real boundaries of our plate tectonics, as well as generate a more complete picture of volcanism on this planet. Some locations of volcanoes are quite surprising, and a lot of research went into this, using my own free time, so I do hope that at least some will appreciate it, elaborate on it, and help me finish this project for the betterment of science, geology, and mankind. Anyhow, look forward to me posting my 'preliminary' database soon, and please feel free to pass it along and enjoy looking at it as much as I had fun making it.

Cheers!

Friday, March 22, 2013

El Hierro Springs Back to Life [updated 4/11]

The now famous island of El Hierro in the Canaries is rumbling back to life. Tremor has increased over the last couple of days with strong volcanic quakes, coupled with even more tectonic quakes. IGN is reporting on the new activity frequently on their social media, and Earthquake-report.com is picking up the story as well with frequent updates to their main El Hierro report blog.

Tremor levels are currently at their strongest since activity slowed down and nearly ceased. The signals indicate that there is magma intrusion very deep within the chamber, at a depth of around 20km (+/- 5km), and inflation of the island is picking up again.

Recent news also determined that aside from the main cone from the last eruption, there was actually a second vent, which some of us including myself had suspected. This vent was far deeper, and not nearly as proiminent as the main vent.

El Hierro could very well be becoming 'active' again, and time will tell in the next few weeks/months if the magma intrusion will continue. I will update this post should anything further develop.

The volcano had caused some headaches for residents, who were hoping for a tourism boom, but the actions of the Spanish media and government had the opposite effect, which ended up scaring away many European tourists, and causing economic woe for La Restinga, a small town on the southern tip of the iron shaped island (El Hierro literally translates to "The Iron"). The town of La Restinga was evacuated for days/weeks otu of concern for gas emissions, and the potential for the submarine cone to enter a Surtseyan type eruption (we now know that it was a Surretyan eruption, forming 'lava balloons' with fluid lava and gas bubbles).

The next phase of the island remains unclear. The island has many cones, and no clear central vent, so it is likely that his pattern would continue. If El Hierro has another eruptive episode, it would likely be another submarine cone building event, or a cone building event on the main island itself, however the seismicity points to a probable submarine event in all likelihood. Still far too soon to tell, and the quakes are still very deep.

****UPDATE 3/22*****

Tremor is consistent and increasing. Deformation is occurring on the West end of the island and pushing it to the East. Hundreds of volcanic tremors are being recorded at depth each day. Sustained tremor will most likely result in rock fracturing, leading to further shallow dike intrusion. Keep an eye on El Hierro (again!).

*****UPDATE 3/28*****

Earthquake activity has been consistently picking up now. Vertical and Eastward deformation is continuous. Quakes are not shallower at depths of 12-9km. magnitude of the quakes is increasing (average from 3.0-4.1) and they are numerous. The epicenters of the quakes are still out to the NW in the ocean, but migrating back and forth farther out, and closer to the island. Residents claim they are feeling constant vibrations on the island, and rockfalls are occurring in the El Golfo area. Tremors now exceed the amount of seismicity that preceded the 2011 eruption, however no eruption is yet imminent, and INVOLCAN and the Spanish government are keeping the island at alert level "Green" for now.

This will most likely change if the quakes get a lot shallower, and magma intrusion continues. For now it appears that this is a massive inflation event, although at depths that would make an eruption impossible for now. If the intrusions reach the 3-1km depths, it would be wise to start worrying. CO2 and other gas emissions continue to be measured on the island and near the previous vent, but so far are stable and show no signs of an imminent eruption. The threat right now is from rockfalls in the unstable cliffs of El Golfo, and damage to lava caves (visitors have been asked not to go exploring due to the possibility of collapses).

*****UPDATE 4/1*****

The rumblings on the island anf deformation are causing rockfalls int he El Golfo area (Northern section of the island, in the 'crater' area, which is technically the area of an ancient landslide event). The unstable cliffs are being disturbed by the deformation and constant rumbles from offshore. People are advised to keep their distance from the cliffs.

PEVOLCA and INVOLCAN (also the Spanish government) are not raising the alert level of the volcano at this time. The earthquakes and magma intrusions are well off shore (abotu 3KM to the West of the island) at depth, so there is no danger to anyone on the mainland unless the intrusions become shallower and closer to the island. So far it looks like the swarm will remain offshore and not bother anyone too badly.

The quakes, aside from the deformation and rock slides, are not causing any damage, although there was a magnitude 4.9 quake the other day that was clearly felt on the island. The seismic crisis is ongoing at this time, and updates are being posted regularly on Earthquake-report.com's website. 

*****UPDATE 4/5*****

The seismicity at El Hierro is calming down at the moment. For the last two days, the earthquakes have decreased in number and magnitude. It is possible that the current magma injection has ceased for now. Deformation remains high, with slight deflation now occurring (things may be settling down). This probably means there will be some follow up quakes as the island 'readjusts' to the inflation and Eastward deformation, but at least for now things are calming down.

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

The seismic crisis seems to have ended as of yesterday (or even the day before, hard to tell). Tremor is back to background levels while a few small aftershock type quakes are happening sporadically. For now, injection of magma into the chamber seems to have ceased, and slight deflation is occurring. Updates have stopped for the most part from INVOLCAN, PEVOLCA, and Earthquake-report.com. The CHIE seismograph on www.ign.es is showing almost flat lines now.

*****UPDATE 4/11*****

As is ever the case with El Hierro, the island's earthquake troubles returned again today with a mag 4.1 quake off the West Coast. Rockfalls were reported in the El Golfo region, and pictures/videos are posted on Earthquake-report.com's El Hierro article.

The Government had lowered the alert from yellow to Green (pre-alert) level, but it remains to be seen whether they keep it there, or if quake swarming will now resume. El Hierro has the habit of start-stop-start when it comes to its activity.

Monday, March 11, 2013

4.6 Mag Quake Strikes Southern California

What a morning! I was sitting at my job out in La Jolla, CA when we felt a slight rumble. Sure enough, USGS was reporting a 5.2 magnitude quake had struck near Anza, CA. The quake was later downgraded to a 4.7, with many, many aftershocks. Now, some local geologists are speculating that this could be a 'foreshock' event, where some moderately sized quakes precede a bigger one.

As much as I like speculation, I highly doubt this is what will occur. First of all, this was not part of the San Andreas fault line, and is part of a very minor fault system. Second, despite many aftershocks, the activity has quieted down quite a bit, leading me to believe that this probably was the main event. The news media really just loves earthquake stories, and will search long and hard to find a scientist that would say "this could be the big one". If I were a betting man, I'd bet against a larger quake in this area.

Covering earthquakes in California below a 5.5 magnitude is probably pointless unless we're talking about quakes near a volcano. the buildings out here are tough enough to survive a magnitude 8.0 tremblor, and that's the law out here. You cannot build buildings unless they are certified quake-safe. Out infrastructure is uniquely adapted to be able to shift. Our Skyscrapers, rather than being rigid, are built to bend and sway (probably a bit disconcerting in the moment, but a lot safer!). Our freeways are built to shift a bit as the quakes move, and diffuse kinetic energy.

My point is, unless the quake is quite large, you probably wont hear of more damage than say, some china falling off a mantle, or a window breaking. And it has been this way for a while.

In any case, the quakes out here in California are pretty normal. The area around Anza, Borrego, and LA county is always experiencing some smallish quakes, I'm certain this quake was just another blip on the radar and nothing to worry about. We all have fun with quakes out here, and have a pretty good chuckle at all the Facebooking and Tweeting from the East coast with stuff like "Praying for you all in CA", or "OMG I hope my friends in CA are OK, so scary!" and so on...

We're fine out here. Send us those thoughts if we ever get a 8.0 or above!