Evolution of the seismic process and crustal total shear strain (2008–2021) under the influence of the Hikurangi mantle superplume

P. A. Dokukin1, V. I. Kaftan2, A. I. Manevich2,3, R. V. Shevchuk2,3,4

1 People's Friendship University of Russia, Moscow, Russia
2 Geophysical Center RAS, Moscow, Russia
3 Mining Institute of NUST MISiS, Moscow, Russia
4 Sсhmidt institute of physics of the Earth RAS, Moscow, Russia

Abstract

In view of the fact that shear deformation is predominant in the focal mechanism of a tectonic earthquake, the study analyzed the accumulation of total shear deformation in triangles of the New Zealand GNSS network. The data of daily determinations of coordinates in the interval 2008/01/01–2021/06/21 were used [1]. The accumulated total shear strains were calculated and digital and graphical models of their spatial distribution were constructed. The resulting images (frames) are combined into a synoptic animation. Observation of the evolution of the deformation process in connection with the development of seismicity made it possible to see the following important features. In the region of occurrence of the Darfield earthquake (September 03, 2010, M 7.1), two and a half years before the event, a significant extremum of total shear strain was formed with a value of ~ 2×10-6. This gives reason to consider it a precursor of a strong seismic event. The strongest aftershock in the Pegasus Bay region also occurred in the zone of this extremum and provoked a tenfold increase in magnitude and the transfer of shear deformation to the area of the Kaikoura Triple Junction. The deformation maximum zone initiated a series of strong and moderate earthquakes in Cook Strait and the coastal area. Subsequently, the source of anomalous shear in 2015–2016 provoked a series of strong events and the strongest Kaikoura earthquake (November 14, 2016, M 7.8) in the zone of high shear deformations of the order of 10-5. An important circumstance is that the maximum accumulated deformation is located in the area of the Kaikoura triple Junction [2], where signs of the existence of a giant mantle superplume have recently been discovered [3].

Database creation date: 2022; Publication date: 23 January 2023

Contributor:
Geophysical Center of the Russian Academy of Sciences, Moscow, Russia
Institution: Geophysical Center of the Russian Academy of Sciences, Moscow, Russia
Publisher: Geophysical Center of the Russian Academy of Sciences (GC RAS), Moscow, Russia (http://www.gcras.ru/eng/)

Data format: .mov (QuickTime File Format)

doi: 10.2205/ESDB-Hikurangi-shear

Citation: Dokukin P. A., Kaftan V. I., Manevich A. I., Shevchuk R. V. (2023) Evolution of the seismic process and crustal total shear strain (2008–2021) under the influence of the Hikurangi mantle superplume. ESDB repository, GCRAS, Moscow, https://doi.org/10.2205/ESDB-Hikurangi-shear

References: 

  1. Blewitt, G., Hammond, W. C., Kreemer C.: Harnessing the GPS data explosion for interdisciplinary science. Eos, 99 (2018) https://doi.org/10.1029/2018EO104623.
  2. Shi X., Tapponnier P., Wang T., Wei S., Wang Y., Wang X., Jiao L. Triple junction kinematics accounts for the 2016 Mw 7.8 Kaikoura earthquake rupture complexity. Proceedings of the National Academy of Sciences, 2019, 116 (52), 26367-2637. https://doi.org/10.1073/pnas.1916770116.
  3. Stern T., Lamb S., Moore J. D. P., Okaya D., Hochmuth K. High mantle seismic P-wave speeds as a signature for gravitational spreading of superplumes. Sci. Adv. 2020; 27 May 2020, Vol. 6, Issue 22, https://doi.org/10.1126/sciadv.aba7118.

License: Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

URL for downloading: http://esdb.wdcb.ru/doi/2023/ESDB-Hikurangi-shear/2022_Dokukin_Kaftan_Total_shear.mov

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