These images show seismic activity over the last 24 hours.
The timestamps shown at the top right of the seismograph drums
shown below are the time when these images were last refreshed. Each horizontal line (or
trace) represents 30 minutes, each vertical line is spaced 1 minute apart; 24 hours of
recording are displayed in total. The most recent signal is drawn at the bottom right
hand corner of the drum. Then read the traces from right to left, bottom to top, to get
from the most recent to the oldest signals. The trace will appear red if the signals are
very large; this means they have been clipped to stop them overwriting too much of the
Tongariro RSAM & SSAM
These images show RSAM and SSAM plots over the last month.
RSAM (Real-time Seismic-Amplitude Measurement) and SSAM
(Seismic Spectral-Amplitude Measurement) are techniques that permit volcano
seismologists to evaluate the nature of seismicity at a volcano. They are able to
recognize subtle shifts in frequency related to changing dynamics of magma or gas
movement within the volcano, or the amount and style of volcanic tremor. They also show
other noise like windy weather or traffic.