How complex is the 2016 M w 7.8 Kaikoura earthquake, South Island, New Zealand?

• Main Authors: Shi, Xuhua, Wang, Yu, Liu-Zeng, Jing, Weldon, Ray, Wei, Shengji, Wang, Teng, Sieh, Kerry
• Other Authors: Earth Observatory of Singapore
• Format: Article
• Language: English
• Published: 2017
• Online Access: https://hdl.handle.net/10356/82097; http://hdl.handle.net/10220/42290
• Institution: Nanyang Technological University

A powerful earthquake of moment magnitude (Mw) 7.8 occurred in the Kaikoura region, South Island, New Zealand, at 00:02:56 AM (local time), 14 November 2016. According to the Institute of Geological and Nuclear Sciences (GNS) in New Zealand, the earthquake epicenter was at 42.69 °S, 173.02 °E, about 90 km northeast of Christchurch, the 3rd largest city in New Zealand (Fig. 1a). GNS reported a focal depth of 15 km. The main shock of the Kaikoura earthquake sequence lasted about 2 min with the most severe shaking occurring about 50 s after the hypocenter origin time. Four large aftershocks of Mw 6.0–6.5 (Fig. 1b) occurred within 13 h of the main shock according to the United States Geological Survey (USGS). The total number of aftershocks exceeded 2000 by 17 November 2016. The rupture exceeded 150 km (Fig. 1a, b), from south of the eastern Hope fault, northeastward, to Cape Campbell, including ∼34 km of offshore rupture along the northeast-trending Needles fault (Ref. NIWA, http://niwa.co.nz/news/scientists-detect-huge-fault-rupture-offshore-from-kaikoura).