What are Halema`uma`u's smoke and other signals telling us?

12-hour seismic record from HVO station NPT, near Halema`uma`u crater, from 7:30AM to 7:30PM HST on August 20. Visible on the record are microearthquakes, volcanic tremor, and tremor bursts. Highlighted at the middle of the figure is the very long-period (VLP) tremor, preceded by a possible rockfall or small earthquake at 3:40PM HST, associated with visible changes in the plume issuing from the Halema`uma`u vent.