Earthquake Swarm Detection Along the Hikurangi Trench, New Zealand: Insights Into the Relationship Between Seismicity and Slow Slip Events

Earthquake swarms, which are anomalous increases in the seismicity rate without a distinguishable mainshock, often accompany transient aseismic processes, such as fluid migration and episodic slip along faults. Investigations of earthquake swarm activity can provide insights into causal relationship between processes seismicity. Slow events (SSEs) plate interface Hikurangi Trench, New Zealand, accompanied by intensive swarms. However, detailed spatiotemporal distribution these swarms is still unclear. Here, we use epidemic-type aftershock-sequence (ETAS) model to detect (M ≥ 3) create new catalog (1997–2015) Trench. We compare with Global Navigation Satellite System (GNSS) time series data, existing SSE tectonic tremor catalogs. Most detected (119) sequences were intraplate events, their epicenters mainly concentrated east coast North Island, whereas many tremors located inland. Twenty-five occurred within 25 days before after eastward GNSS displacements due known or newly SSEs. find that sometimes preceded more than several days. SSE-induced stress loading therefore not plausible triggering mechanism for pre-SSE propose high pressure slab, accumulated SSEs, may have caused migration, turn triggered