Subsidence determination in the Central Valley, California

Abstract

Twenty four hour GNSS (Global Navigation Satellite System) data acquired monthly for 5 years from 8 CORS (Continuously Operating Reference Station) stations in Central Valley, California are processed and vertical velocities of the points are determined. To process GNSS data, online GNSS data processing service APPS (Automatic Precise Positioning Service) is used. GNSS data downloaded from NGS (National Geodetic Survey) CORS are analyzed and subsidence at these points is portrayed with graphics. It is revealed that elevation changes range from 5 mm uplift in the north to 163 mm subsidence in the southern part of the valley.

Deformation analysis in central west Bulgaria using triangulation and GPS data

“…GNSS measurements allow observation of the recent tectonic activity because they provide quantitative assessments of crustal movements in studied areas. Previous studies have shown the applicability of such a method in geodynamic areas with high horizontal and vertical deformation rates such as the western United States (Dong et al, 1998), central west Bulgaria (Dimitrov and Georgiev, 2011), Central Valley, California (Romero and Berber, 2018) and so on. Global Positioning System (GPS) data provide a good opportunity to study the current geodynamic processes, but the basic question arising in this case is how far the present-day results can be extrapolated back in time.…”