Houston, Texas, is one of the earliest urban areas to employ Global Positioning System (GPS) technology for land subsidence and fault monitoring. As of 2020, the University of Houston and the Harris-Galveston Subsidence District have integrated over 230 permanent GPS stations into their routine GPS data processing for regional subsidence and fault monitoring. This article summarizes the GPS geodetic infrastructure in the Greater Houston region.

This study presents an integrated approach to evaluate inundation risks, in which an algorithm is proposed to integrate the storm water management model (SWMM) into a geographical information system (GIS). The proposed algorithm simulates the flood inundation of overland flows and in metro stations for each designed scenario. It involves the following stages: (i) determination of the grid location and spreading coefficient and (ii) an iterative calculation of the spreading process.

The study establishes the first local reference frame for the Gulf of Mexico region using the observations from 13 GNSS sites. The root mean square (RMS) of the velocities of the 13 reference stations achieves 0.2 mm yr⁻¹ in the horizontal and 0.3 mm yr⁻¹ in the vertical directions. Land subsidence, faulting, and salt dome activities in the Houston region, Mexico City, and the southeastern Louisiana region are discussed and compared.

These exists a new phenomenon with continuous deformation in the sandy aquifers in Shanghai. Sharp hydraulic gradient would be formed in the aquifer and shear stresses would develop. Cumulated shear stress is one of the main factors that contribute to deformation within an aquifer. Cosserat continuum mechanics can be applied to analyse the mechanism of confined aquifer deformation controlled by accumulated shear stress.

Two additional alternative mechanistic models are proposed that involve principles of load transfer considering the temporally and spatially redistributed stresses associated with groundwater extraction: i) Cosserat continuum mechanism, considering shear force in the aquifer due to hydraulic gradients in the aquifer; and ii) internal erosion of fine-grained (clay and silt) particles within the aquifer. Initial results based on simulations incorporating Cosserat mechanics look promising.