The following two images were acquired by a remote camera at station BRUTUS on the northeast rim of the 1980 crater at Mount St. Helens. The first image.

The following two images were acquired by a remote camera at station BRUTUS on the northeast rim of the 1980 crater at Mount St. Helens. The first image was taken at 18:10:59 PST on February 18, 2008. The second image was taken 48 hours later at 18:10:27 PST on February 20, 2008 (camera times accurate to ± 1 minute). View is to the southwest. The 2004-2008 lava dome fills most of the images; a portion of the 1980-1986 dome is visible in the lower right corner.

The same set of triangles appear as control points in both images to mark distinctive features and to help assess whether any movement occurred during the interval between images. Black triangles mark features on the southwest crater wall, which were used to precisely register the images. Blue triangles mark features on the 1980-1986 dome. Yellow triangles mark features on the 2004-2008 dome. Red triangles mark features in the central part of the 2004-2008 dome, which was active near the end of the eruption (“Spine 8”).

Earlier in the eruption, dome growth could be discerned in images like these taken as little as 1 hour apart, and it was obvious in images taken 1 day apart. In this case, no motion is evident anywhere in the scene when the images are viewed sequentially, except for minor changes in snow and in talus near the lower left edge of the images.

Initially the change from one image to the next is slow to allow the viewer time to become familiar with the scene and control points. Then the rate becomes progressively faster to facilitate the comparison. Note especially the lack of perceptible motion at “Spine 8” (red triangles).

20080218181059 Crater wall 2004-08 dome “Spine 8” 1980-86 dome 20080218

Based on this evidence and data from a temporary GPS station deployed to “Spine 8” on February 15, 2008, which detected only motion consistent with gravitational settling, USGS/CVO issued an eruption update on February 21, 2008, stating that “…volcanic activity has decreased significantly…” On July 10, 2008, USGS/CVO declared: “The more than three-years-long, lava- dome eruption of Mount St. Helens that began in autumn 2004 and paused in late January of this year appears to have ended.”

The following two images were acquired by a remote camera at station BRUTUS on the northeast rim of the 1980 crater at Mount St. Helens. The first image.

Similar presentations

Presentation on theme: "The following two images were acquired by a remote camera at station BRUTUS on the northeast rim of the 1980 crater at Mount St. Helens. The first image."— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

The following two images were acquired by a remote camera at station BRUTUS on the northeast rim of the 1980 crater at Mount St. Helens. The first image.

Similar presentations

Presentation on theme: "The following two images were acquired by a remote camera at station BRUTUS on the northeast rim of the 1980 crater at Mount St. Helens. The first image."— Presentation transcript:

Similar presentations

About project

Feedback