Seismicity of the Lake Taupo region, New Zealand, 1985-90

Abstract

Earthquake activity in the Lake Taupo region during 1985–90 was dominated by the repeated occurrence of sequences of small earthquakes, and statistical analysis confirms that clustering was present. Earthquakes were concentrated beneath the central, eastern, and southern parts of the lake, with the Tokaanu, Motuoapa, and Te Hapua Bay areas being the main sites of repeated sequences. Western Bay, the western Taupo Fault Belt, and an area near the southwestern shore of the lake were almost aseismic. Almost all earthquakes occurred within the 15 km thick crust, with a concentration at 4 km depth. The distribution of earthquakes during 1985–90 contrasts with previous studies which snowed a concentration of seismicity in Western Bay and near the southwestern shore of the lake. The tendency for earthquakes to be concentrated in certain areas, together with large changes in the rate of activity, cause significant problems for the identification of earthquake sequences that may be precursors to volcanic activity. © 1992 Taylor & Francis Group, LLC.