PNSN catalog near Mount St Helens

May 14, 2012

by John Vidale

 For now, I'll simply post the map of events in our catalog.  Light blue circles are earthquakes, red and pink are explosions, and white circles are unknown.  Somewhere under the thousands of little earthquakes at MSH are the eruptions.

One task with our new and more capable software is to check that the events are categorized as well as possible, location accuracy improved, and interpreted sensibly.

Just provide orientation, the dense ball of activity in the lower right is Mount St Helens, the vertical stripe of seismicity in the St Helens Fault Zone.

Actually, my interest was spurred by the apparent lineation of 10-15 km deep seismicity in the last day (orange circles, hard to see) that define a similar trend to the St Helens Fault Zone, but offset about 10 km west.