Abstract. We have delineated ten years of urban subsidence derived from
continuous GPS stations operated by the Crustal Movement Observational
Network of China (CMONOC) within and adjacent to the municipality of
Tianjin. A method for obtaining accurate site velocities with respect to a
stable regional reference frame is described. CMONOC stations in Jizhou
(JIXN) and Baodi (TJBD) districts recorded minor subsidence of approximately
1 to 2 mm yr−1 during the period from 2010 to 2019. One station in Wuqing
(TJWQ) district and one station in Binhai (TJBH) district recorded steady
subsidence of approximately 5 and 2 cm yr−1 from 2010 to 2019,
respectively. One station in Cangzhou (HECX) of Hebei Province, adjacent to
Tianjin, recorded steady subsidence of approximately 2.4 cm yr−1 during
2010–2014 and more rapid subsidence of 4 cm yr−1 since 2015. TJWQ recorded
the most rapid land subsidence and the most significant seasonal ground
oscillations (uplift and subsidence) among these five stations. This study
indicates that subsidence rates in Tianjin vary significantly in space and
time. Particular attention should be paid, therefore, to extrapolate or
infer a rate of subsidence for an area on the basis of a subsidence rate
obtained from previous GPS observations or proximal GPS sites. The
subsidence time series presented in this study provide reliable “ground
truth” and constraints for calibrating or validating subsidence estimations
from numerical modeling and repeated surveys using other remote sensing
techniques, such as Interferometric Synthetic Aperture Radar (InSAR).
Crustal deformation of the Yellowstone–Snake River Plain volcano-tectonic system: Campaign and continuous GPS observations, 1987–2004
