Tectonic classification of vertical crustal motions – a case study for New Zealand

  • Robert TENZER The Key Laboratory of Geospace Environment and Geodesy, School of Geodesy and Geomatics, Wuhan University
  • Ali FADIL National School of Surveying, Faculty of Sciences, University of Otago
Keywords: GPS, tectonic setup, vertical crustal motion, volcanism

Abstract

We investigate the relationship between vertical crustal motion and tectonic
block configuration. The study is conducted along the active tectonic margin between
the Australian and Pacific tectonic plates in New Zealand with a well-defined tectonic
block configuration. For this purpose, the rates of vertical crustal motions relative to the
ITRF2008 reference frame are estimated based on processing the GPS data (provided by
the GeoNET project) collected at 123 continuous and semi-continuous GPS sites. The
numerical results confirmed the uplift of the central Southern Alps at the current rate
of 4.5 mm/yr. This tectonic uplift is coupled in the South Island by the subsidence on
both sides of the Southern Alps. The detected rates of subsidence in the eastern South
Island are typically less than 1 mm/yr. The subsidence in the Buller Region (in the
northwest South Island) is 1.4–1.5 mm/yr. Except for the Taupo Volcanic Zone and the
upper Raukumara Block (in the central and northeast North Island), the subsidence is
prevailing in the North Island. The systematic subsidence up to 9 mm/yr is detected
along the Dextral Fault Belt (in the lower North Island). The largest localized vertical
displacements (between −10 and 17 mm/yr) in the Taupo Volcanic Zone are attributed
to active tectonics, volcanisms and geothermal processes in this region. A classification of
these vertical tectonic motions with respect to the tectonic block configuration reveals that
most of tectonic blocks are systematically uplifted, subsided or tilted, except for regions
characterized by a complex pattern of vertical motions attributed to active geothermal
and volcanic processes.

Author Biographies

Robert TENZER, The Key Laboratory of Geospace Environment and Geodesy, School of Geodesy and Geomatics, Wuhan University

129 Luoyu Road, Wuhan, 430079, China

Ali FADIL, National School of Surveying, Faculty of Sciences, University of Otago

310 Castle Street, Dunedin, New Zealand

Published
2016-06-30
How to Cite
TENZER, R., & FADIL, A. (2016). Tectonic classification of vertical crustal motions – a case study for New Zealand. Contributions to Geophysics and Geodesy, 46(2), 91-109. https://doi.org/10.1515/congeo-2016-0007
Section
original research papers