Interesting...no specific seismic signature before the eruption - this is a steam and ash (phreatic) explosion - and it looks like successive steam and ash explosions occuring. This event is much longer than the last three.
I'll bet a dollar that there will be an explosive eruption at some time soon. With all the commotion going on now, and with all that glacier water melting down into the hot magma, something's gonna happen.