Monday, October 04, 2004

I arrived back in Portland yesterday afternoon, and was met by my mom at the airport because she happened to be in town. Great timing, since Mt. St. Helens is coughing up steam and stuff these days. We made some stops along the drive home to look at the mountain (there are lots of great viewpoints near where I live). This morning we watched the big steam venting out of the crater, and then we drove back to the airport for her flight home.

Image, click to enlargeIt looks like the volcano is getting ready for something bigger. I have tried to estimate my house's distance from the volcano, because people keep asking (I assume out of concern). It looks like I live somewhere between 40 and 45 miles from the volcano (I will map it out sometime soon). So, no fears - the worst thing that would happen here is ash fallout (which can be problematic if you breathe it or get it in your eyes, and it's nasty on car paint and windows). But the winds at the mountain are blowing directly away from here right now. If it's going to blow, I just hope it happens when I am home, so I can snap some pictures and watch. And, in true form, Dan Appleman (whom I met at the conference last week) has some funny observations on volcanoes and politics that will generate a laugh or two. (Image by USGS, click for more pictures, or for seismographic info from the Cascade Mountains)

USGS Update: Mount St. Helens Update 4 October 2004 7:00 P.M.

Current status is Volcano Alert (Alert Level 3); aviation color code RED

This morning visitors to Mount St. Helens witnessed a 40-minute-long steam-and-ash emission starting at 9:43 PDT. Steam clouds carrying minor ash billowed out of the crater to an altitude of 10,000 to perhaps 12,000 feet. The event did not generate earthquakes or an explosion signal. We infer that hot rock was pushed up into the glacier, melted ice, and generated the steam. Part of the vent for today’s and other steam and ash emissions of the past few days is now covered by a boiling lake. The emission occurred during a time of gradually increasing seismicity, which dropped slightly after the emission, but continued to increase gradually through the afternoon. Another period of smaller steam and ash bursts occurred between 2:10 and 2:40 P.M. Visual observations show that the area of uplift, which includes part of the glacier and a nearby segment of the south flank of the lava dome, continues to rise. We infer that magma is at a very shallow level and could soon be extruded into the vent or elsewhere in the deforming area. Additional steam and ash emissions are likely and could occur at any time without warning. Conditions suggest that there is also an increased probability of larger-magnitude and more ash-rich eruptions in coming days.

Yesterday’s gas-sensing flight detected slightly lower concentrations of carbon dioxide in the crater, but for the first time the airborne instruments detected the presence of hydrogen sulfide. Wind conditions during today’s flight should permit the first estimation of the rate of gas flux.



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Mt. St. Helens | Random Stuff
Monday, October 04, 2004 6:31:06 PM (Pacific Standard Time, UTC-08:00)
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