Monitoring techniques provide insight into Mount St. Helens' behavior.

Since the end of the 2004-2008 dome-building eruption, scientists have been monitoring subtle inflation of the ground surface and minor earthquake activity that is reminiscent of that seen in the years prior to the 2004-2008 eruption.

Careful analysis of these two lines of evidence now gives us confidence to say that the magma reservoir beneath Mount St. Helens has been slowly re-pressurizing since 2008. It is likely that re-pressurization is caused by arrival of a small amount of additional magma 4-8 km (2.5-5 miles) beneath the surface. This is to be expected while Mount St. Helens is in an active period, as it has been since 1980, and it does not indicate that the volcano is likely to erupt anytime soon. Re-pressurization of a volcano's magma reservoir is commonly observed at other volcanoes that have erupted recently, and it can continue for many years without an eruption.

To learn more, field work this summer will include measuring the types and amounts of gases being released, and the strength of the gravity field at the volcano. The information collected at Mount St. Helens continues to help scientists analyze behaviors here and at other volcanoes and to improve eruption forecasting capabilities. View the full Mount St. Helens Information Statement April 30, 2014 and read the Abstract: Evidence for Ongoing Magma Recharge at Mount St. Helens, Washington. Sign up for the Volcano Notification Service to receive your own updates about volcanic activity at Mount St. Helens or other volcanoes. Read more about Monitoring Mount St. Helens online.