The red squares on the map indicate the location of the Meteorological Office seismometers. The tremor graphs show average vertical movement per minute for each seismometer, in three frequency ranges (Hz).The vertical axis has the same scale for each station. The main purpose of these graphs is to monitor changes in intensity of seismic wave motion. The absolute value of the scale has no meaning. Many phenomena can influence the intensity, for example wind, ocean waves and  traffic. Sometimes floods and volcanic tremor can be detected. Earthquakes appear as spikes on the graphs. From here you can view tremor plots from all our seismic stations.