Example of OBS seismograms of an earthquake. The vertical component and one component of the two horizontal sensors for each OBS are shown. The origin time of the event is 21:32:10.5 UTC on 1994 September 1 and the estimated coordinate of the hypocentre is 9° 25.7′S, 159° 25.8′E. The depth and magnitude of the event are 23.8 km and 2.5, respectively. Each trace is normalized to its maximum amplitude. OBS number and component are labelled above each trace. Solid inverted triangles and open inverted triangles indicate P- and S-wave arrivals, respectively.