Unlocking the secrets of slow slip using next-generation seismic experiments

Abstract

This report documents the acquisition and archiving of data collected using NERC GEF SEIS-UK 6TD seismometers during a major 3D active-source and passive seismic imaging experiment, NZ3D-FWI in 2017-2018. The NZ3D-FWI project aims to image the Hikurangi subduction zone (upper and lower plates and plate boundary fault) along the north Hikurangi margin, New Zealand where shallow slow slip events occur. The primary aim of the project is to collect data optimally to produce high-resolution active-source seismic velocity models using Full-waveform inversion (FWI). This deployment was part of a much larger experiment involving the collection of offshore 3D seismic reflection data and the deployment of 99 Ocean Bottom Seismographs. The onshore NZ3D-FWI deployment covered a 15 x 30 km area and included 49 CMG-6TD broadband seismometers from GEF deployed from December 2017 to October 2018, which detected airgun shots from the 3D seismic reflection survey and local and teleseismic earthquakes over the 9 month period. 119 short-period DATACUBE3 instruments loaned from GIPP Potsdam and 25 short-period GSX3 instruments from the Earthquake Research Institute (ERI), Tokyo were also deployed onshore between December 2017 and February 2018. The full NZ3D-FWI experiment is described in detail in the published report referenced below. This short report will focus only on the NERC GEF provided equipment.