Observations of Deep and Shallow Seismicity Within the Wairakei-Tauhara Geothermal System

Abstract

Over the lifetime of the Wairakei Seismic Network (2009 to present), deep microseismicity (> 4 km depth) has been consistently detected near the north-western part of the Wairakei field including outfield areas. Episodes of deep microseismicity often correlate temporarily with shallow (< 4 km depth) microseismicity detected near production and injection areas of Wairakei and northern Tauhara. In order to better understand the meaning of this deep microseismicity – in terms of its connection with the Wairakei-Tauhara geothermal system, selected swarms of deep microseismicity detected over the period Jan 2013-March 2015 were studied against field operating history. The temporal correlation between deep and shallow microseismicity is discussed in the light of evidence presented here.