I spend a lot of time monitoring the volcanoes of the Aleutian arc, such as I am able to given that only a few out of the 90 or so volcanoes there have web accessible seismographs and lately Mt. Augustine looks quite interesting on those (for all the wrong reasons), but there are none on Mt. Cleveland. To keep up with what that one is doing one has to rely on reports from pilots and satellite photos. AVO tells us:
“Without a real-time seismic network on the volcano, AVO is unable to track local earthquake activity related to volcanic unrest, provide forecasts of eruptive activity, or confirmation of explosive, ash-producing events. AVO is monitoring the volcano using satellite data as it becomes available. Such data suggests that effusive eruption of the lava dome in the summit crater is possibly continuing.”
Okay, fair enough guys, but how come you couldn’t just steal a seismograph from Mt. Wrangell (which has been doing absolutely nothing forever) and put it there? Mt. Cleveland is far more interesting. Well I guess not, because AVO tells me that it would cost them up to $250,000.00 to instrument Mt. Cleveland, and much as they would like to do it funding is an issue. No surprise there in this economy.
Fortunately we do have a pretty good picture of the lava dome building in the crater there.
Now this lava dome, as you other volcanogeeks well know could contribute to an explosive eruption as it grows and plugs up the vent. There have been lava flows running down the flanks of the volcano for some time now, and as that magma comes up the vent of the volcano it sticks to the lava dome in the crater, continuously adding to it in an all too familiar scenario preceding many other violent plinian eruptions, Mt. St. Helens being a recent example.
What happens is that the magma cannot get out of the vent, and the mountain starts swelling as magma intrudes into every crack and crevice it can work it’s way into. Eventually the pressure blows the cork in the central vent, or in extreme cases, such as St. Helens, it produces a lateral eruption, blowing out an entire flank of the volcano.
Fortunately no one lives on the island Cleveland is on, so there are not likely to be civilian casualties, unless a plane flies through it’s ash cloud and crashes into the sea. It’s located as shown below:
Cleveland has of course erupted in the past, and we have an excellent picture of it’s eruption in May of 2006.