According to PNSN, 88 earthquakes rattled Mount St. Helens in the last 30 days. As shown in the map below, they all lie within the crater.
PNSN also explains on their website that:’[…] on average (not during eruptions or their precursors) they locate about 17 earthquakes a month at Mount St. Helens […].‘
So 88 quakes are a lot more (a difference of 71 from the monthly average)…
These latest tremors hit at a depth between -1.8 (-1.1 miles) and +10.6km (6.6 miles), with the majority of them being in the depth range 2-4 km (1.2-2.4 miles).
These quakes are related to stresses generated by magma recharge into the main crustal magma system.
According to PNSN, such recharge seems to have taken place during the periods: 1989-1991, late in 1995 in 1997 and perhaps a few periods since the end of the last eruption such as mid 2014 and 2016. And also perhaps beginning of this year, as shown in the diagram below:
Although the seismic activity has decreased over the last 2 days, this new sequence of earthquakes clearly demonstrate that Mount St. Helens is prepring for the next eruption… Just be ready for the next Big explosion!