Exceptionally deep earthquakes in the northern South Island, New Zealand

Abstract

The intermediate depth seismicity of the northern part of the South Island has been found in the past to extend to a maximum depth of about 230 km. On 1990 Jun 22, an event occurred which was routinely located at a depth of 348 km in this region. Subsequently, a data search revealed another event in 1988 of similar depth and location, less well determined but acceptable. Both events have a magnitude M_L = 3.4–3.5. In the future, consideration of the deep structure in this region should take into account the possible extension of seismicity to greater depths.

Keywords:

• deep earthquakes
• New Zealand
• subduction