The Hikurangi Margin Continuous GNSS and Seismograph Network of New Zealand

Abstract

Online Material: Tables of GNSS and seismograph station details. ### Overview The Hikurangi margin geophysical monitoring network (HiMNet) is a telemetered network of 49 short‐period (1 s) seismometers and 80 continuously recording Global Navigation Satellite System (GNSS; currently based on the Global Positioning System [GPS] constellation) stations in the Hikurangi subduction margin forearc, New Zealand. HiMNet was established between 2001 and 2011 to monitor continuous and transient deformation and seismic activity near the Hikurangi subduction zone. The resulting data have enabled the contemporary behavior and earthquake potential of the Hikurangi subduction zone to be better understood and for earthquake and ground deformation assessments to be carried out with increased precision immediately following geologic events. In this paper, we discuss the design and installation of HiMNet, as well as data handling, availability, and quality. We demonstrate the success of the network by highlighting scientific and event response advancements that are underpinned by the HiMNet data. These include the discovery of transient slow‐slip events (SSEs) in New Zealand (Douglas et al. , 2005; Wallace and Beavan, 2010; Wallace et al. , 2012), the detection of seismic tremor in New Zealand (Fry et al. , 2011; Kim et al. , 2011), and faster and more accurate earthquake solutions. The benefits of the improved network coverage are demonstrated by presenting the event summaries of four damaging earthquakes (the 2007 Gisborne, 2013 Cook Strait, 2013 Lake Grassmere, and 2014 Eketahuna earthquakes; Francois‐Holden et al. , 2008; Hamling et al. , 2014) that occurred within the HiMNet region between 2007 and 2014. ### Tectonic Setting The onshore accessibility of much of the forearc makes the Hikurangi margin an ideal setting for monitoring seismic and aseismic deformation related to subduction interface processes. The Hikurangi plateau, which comprises thick oceanic lithosphere of Cretaceous age (Mortimer and Parkinson, 1996), is being subducted beneath the eastern North Island …