volcanic hazards
eklemetti | July 12, 2008
Okmok Caldera in Alaska's Aleutian Islands erupted today, sending an ash column to at least 30,000 feet. Very little news has been released about the eruption so far beyond this information about the eruption column and some bits about precursor seismicity. A number of flights to Unalaska Island were cancelled due to the eruption. I'll pass on more information when I get it.
Okmok is located near Dutch Harbor, Alaska and is a large shield volcano with two prominent calderas at the top. In fact, whenever I see pictures of the caldera, I am reminded of what Crater Lake (Oregon) might look…
eklemetti | July 11, 2008
Some news of a series of small eruptions at San Cristobal in Nicaragua. Ash from the small explosions drifted to a town near the volcano, however officials for Ineter in Nicaragua say that there is little chance of a large eruption.
San Cristobal is one of the seven active volcanoes in Nicaragua. It has a long record of small eruptions, with at least one every year in the 21st century (and beyond). The largest eruption in recent times was in 1999 that produced lahars and an explosive eruptions (landing us at VEI 2).
eklemetti | July 10, 2008
Llaima (Chile) is experiencing an increased tempo in its current eruption. The National Emergency Office in Chile is reporting that the eruption has begun to take a more explosive character, with pyroclastic material being shot hundreds of meters from the main vent. Although the officials have not changed the current status of the evacuation, which has been limited to 50 people closest to the volcano, they are pondering their next step if the week-old eruption continues to escalate.
eklemetti | July 8, 2008Â
Kilauea is busy keeping geologists and tourists alike wondering what the volcano will be doing next. The current report on the volcano tells of a new fire fountain at the Thanksgiving Eve Break-out "rootless cone", about 6 miles from the ocean. The fire fountain started on Sunday night, issuing lava up to 40 feet in the air and the USGS has posted an amazing video of the fountaining on the HVO website. However, unlike the predicted behavior where magma at Kilauea starts near the summit and moves into the rifts, these lavas appear to be unrelated to the activity going on at the summit of…
eklemetti | July 4, 2008[wp_caption id="" align="alignnone" width="400" caption="Anak Krakatau"][/wp_caption]
Indonesia's Volcanology and Geological Disaster Mitigation Center of the Ministry of Energy and Mineral Resources (whew, that is a mouthful) has placed Anak Krakatau on high alert for increased activity. Tourists were warned not to climb on the volcanic island in the Sunda Straits that rises from the remnants of the famous 1883 eruption of Krakatau. Anak Krakatau formed within the caldera of the ancestral volcano and have been fairly active since the 1920's, producing incandescent bombs and small ash…
eklemetti | July 4, 2008[wp_caption id="" align="alignnone" width="360" caption="Llaima 2008"][/wp_caption]
The current eruption at Llaima in Chile is causing some concern about flooding in the Rio Calbuco near the volcano. The lava flows are melting snow on the volcano and this is being exacerbated by heavy rain in the area as well. The eruption seems to have waned some according to the governor of the region. This all follows the evacuations of people near the volcano and the red alert issued by the Chilean government. (The picture of Llaima is from the January 2008 eruption.)
eklemetti | July 2, 2008
There are some astounding new pictures of Chaiten in full eruption over at the Smithsonian Website. There pictures were released by the USGS/VDAP team and show a full eruption column coming from the new dome in the Chaiten caldera (see above and below). The dome itself looks giant, filling up a lot of the old caldera (the highlands around the edge of the dome itself). The eruption is almost the antithesis of the 2004-08 Mt. Saint Helens dome eruptions which has produced a minute dome filling the 1980 crater. This rhyolite dome is the first major rhyolite eruption in almost 100 years, so I…
eklemetti | July 1, 2008
Update 7/2/08: Sounds like the lava flows from Llaima are increasing ... or that there are more of them. The lava flows, as mentioned below, pose a threat to melt the ice on the volcano and produce lahars, or at least flooding.
Lots of news this morning about a new eruption at Llaima in Chile. The composite volcano is in south central Chile (the lakes region) about 430 miles south of Santiago. This is at least the third time this year that Llaima has erupted, and this time a lava flow is heading down the volcano towards the Rio Calbuco as far as 800 m downslope. The fear is the lava flow…
eklemetti | June 29, 2008
Almost 9 months since its last eruption, Ruapehu is keeping New Zealanders guessing about its next move. Brad Scott of GNS Science (NZ) reports that the crater lake at Ruapehu is reading unusually warm temperatures and high gas emissions, well after geologists there would have expected after the last eruption. Their conclusion doesn't seem to point to an imminent eruption, but rather just "unrest" at the volcano. Ruapehu is a fairly unique situation, mitigation-wise, as the volcano is a popular tourist destination for its skiing, but is also a relatively active volcano. This means that…
eklemetti | June 26, 2008I found this picture on the SF Chronicle website and it speaks volumes about the destruction wreaked on Chaiten, Chile.
The ash has buried the town and what the ash hasn't damaged, the water and debris from the swelled river in the background have finished off. This is what volcanoes can do in the blink of an eye (geologically speaking).
eklemetti | June 25, 2008
Since the "surprise" eruption of Chaiten in southern Chile (still erupting away), I'm sure there has been a lot of talk about better monitoring and predictions for volcanic eruptions. Now, we don't know the full extent of the facts, but usually an eruption of the magnitude of Chaiten (VEI 6, i.e., BIG) don't just go off out of the blue. There are precursors, such as seismicity under the volcano, uplift of the land over the volcano (think of the bulge of Mt. Saint Helens prior to the 1980 eruption), increasing emissions of volcanic gases such as carbon dioxide or sulfur dioxide, increase in…
eklemetti | June 24, 2008
If Alaska wants to take a cue from Iceland, it might find itself with more power than it can use. That is, if the dreams of the Alaska Division of Oil and Gas come true. They are planning to lease land on Mt. Spurr and possibly Mt. Augustine for geothermal exploration. Both of these volcanoes are active, with Mt. Spurr erupting last in 1992 (famously almost taking out a KLM 747 due to volcanic ash EDIT: Oops, this was not Spurr in 1992, but Redoubt in 1989. Luckily, AVO knew to warn aviation about the Spurr eruption thanks to the lessons learned from the near disaster at Redoubt) and…
eklemetti | June 23, 2008
Things have quieted down on the volcano-news front lately. I did catch a report that Fuego (Guatemala) is having small explosions (stombolian eruptions; link in Spanish), producing small (100s m-tall) ash columns along with some throwing incandescent blocks 30-50 meters from the vent. Just the typical noises expected at an active volcano. In the meantime, you can check out the volcanic hazards information that the Guatemalan survey (INSIVUMEH) has posted on their website. I'm always a fan of a country trying to educate their citizens of the real dangers of volcanoes and how to prepare.
eklemetti | June 19, 2008
Just when you thought it was safe to go outside.
After apparently settling down a bit over the weekend, Chaiten has kicked it back up a notch. The latest reports say that two ash columns are active ... and that is about all we get for more news. Not surprisingly, most of the damage around the volcano has been done by flooding and/or lahars, thanks to the ash and debris-choked rivers like Rio Blanco. It also sounds like the SERNAGEOMIN is digging in for the long-haul, calling for the eruption to go on - to some degree - for months. This isn't too shocking considering the minor dome eruption…
eklemetti | June 16, 2008
I am always amazed by the number of volcanoes that show signs of activity every year that I have never heard of before. Case in point is this report of activity near Mr. Kurikoma, on the island of Honshu in Japan. The last known eruptions at Kurikoma were back in 1950, and they seem to be water-magma interactions that produce phreatic explosions - and even beyond this 1950 eruption, there isn't much information about the eruptive history at Kurikoma.
However, if you look at the report, the activity is actually rather far from the summit of Kurikoma - a full 7 km to the southwest. There are…
eklemetti | June 16, 2008
The newest reports out of Chile are indicating that the eruption at Chaiten has reached levels of intensity not seen since the eruption first started over six weeks ago. I have to admit, that isn't a good sign in terms of keeping the volcanic edifice in one piece. There have been frequent, small (<M3) earthquakes along with "rumbling noises," which might indicates that the domes are collapsing to form pyroclastic flows. Alternately (and need I remind you, very speculatively) it might be the the edifice itself beginning to show the wear of this long eruption and the emptying of the magma…
eklemetti | June 14, 2008
Just a quick update for today (busy watching Red Sox vs. Reds, sorry, that is my other love: baseball). New reports concerning White Island suggest that an eruption is not imminent. Although there have been earthquakes nearby, whether or not they could directly lead to an eruption is unclear, but it sounds like geologists in New Zealand on trying to be cautious. This is the fun/challenge of predicting and monitoring volcanoes - the signs might be there, but you never know if the signs are all leading the same way.
eklemetti | June 13, 2008
So, this was a bit of a surprise to me. Six weeks into the Chaiten eruption in Chile, apparently the volcano has picked up the tempo again. Not much in the report except that apparently two new vents/craters have opened, there is an increase in ash emission and seismic activity. What this might be is difficult to ascertain from the report, but it could indicate that the volcano might be heading down the road toward a collapse, such as the one previously alluded to by scientist-in-charge Luis Lara. Another report - albeit almost identical to the first - does mention in the headline that the…
eklemetti | June 13, 2008
Authorities in New Zealand have issued an alert for White Island. After a fairly sizable earthquake (M=5.4) near the island, the state agency that oversees volcanoes (GNS Science) is warning people to stay away from White Island for the next 48-72 hours on fears it might erupt. Normally, just because there is an earthquake near a volcano you don't instantly jump to the idea that it will erupt, but the 5.4 and subsequent earthquakes have been both near White Island and shallow (5-km depth), indicating it could very well be related to magma moving under the system.Â
White Island itself is a…
eklemetti | June 10, 2008
One of the most famous eruptions in human history (at least recent history) is the 1883 eruption of Krakatau in Indonesia, made (more) famous by Simon Winchester's book (and the inappropriately named film Krakatoa: East of Java ... hint: look at a map). Since the cataclysm eruption, a new volcano has risen where the old one once stood. Anak Krakatau (I believe loosely translates to "son of Krakatau") is a fairly active volcano, producing Strombolian explosive eruptions - fairly mild - that threw volcanic bombs and debris onto the island and into the surrounding ocean (thus, building up the…