Remote Triggering of Microearthquakes and Tremor in New Zealand following the 2016 Mw 7.8 Kaikoura Earthquake

We conduct a systematic search for remotely triggered seismicity in New Zealand following the 2016 M-w 7.8 Kaikoura earthquake. We first examine seismicity rates obtained from the GeoNet catalog one month before and after the Kaikoura mainshock. We find a clear increase of microseismicity following the mainshock in the North Island, mostly along the shallow portion of the Hikurangi subduction zone, as well as surrounding and to the east of the Taupo volcanic zone (TVZ). We then examine high-frequency seismic signals during and immediately following the large-amplitude surface waves and identify instantaneously triggered events at several new sites. These include long-duration tremor-like signals in low-strainrate regions around Auckland, near the source region of the 2009 M-w 7.9 Dusky Sound earthquake in the southern South Island and at several sites within and south of the TVZ. Triggered signals along the TVZ likely originated from multiple sources. A common feature of these instantaneous triggering sites is their close proximity to hot springs or elevated subsurface temperatures associated with active volcanoes or fault structures, suggesting that they may provide necessary conditions for remote dynamic triggering.