Trends in horizontal and vertical crustal displacements based on international GNSS service data: a case study of New Zealand

Abstract

The study analyzes the coordinate time series of five permanent International GNSS Service (IGS) stations located in New Zealand. It also considers their annual movement from 2009 to 2018. The raw data in the form of Receiver Independence Exchange (RINEX) files were taken from IGS database and processes by means of online processing service AUSPOS. Using coordinate time series, horizontal and vertical displacement rates were calculated covering the ten-year study period. According to the results, stations located at the North Island of New Zealand revealed an uplift of 31-32 mm/yr. At the same time, stations placed on the South Island showed the 21-22 mm/yr of positive vertical displacement. Regarding the horizontal displacements, their rates increase in North-South direction over the study region. In particular, two stations of North Island, located at the North-Western part, appeared in 24-25 mm/yr displacement, and one station at the Southern part of North Island showed the 35 mm/yr displacement rate. Stations, established at South Island, showed the horizontal displacement rates of 41-56 mm/yr. This research confirms the main contribution made to the field of crustal deformation studies, including the updated values of displacements along with their directions over the recent years. The results of this study can be used for further geodynamics investigations as well as for finding the most likely earthquake locations of the current study area.