Crustal Structures Impacting the Ascent of Deep Magmas Near Mount St.

Geophysical expression of crustal structures impacting the ascent of deep magmas near Mount St. Helens. Colors show electrical resistivity at 7 kilometers depth. Seismicity shown as black dots, major volcanoes as yellow triangles, and other volcanic vents as pink circles. Deep long-period earthquakes, suggestive of deep fluid transport, are shown as green stars.