Geology topics

Shujun Ye

Publications and source records attributed to Shujun Ye.

3 recordsLinked to original sources

USGS2021

Mapping the global threat of land subsidence

Subsidence, the lowering of Earth's land surface, is a potentially destructive hazard that can be caused by a wide range of natural or anthropogenic triggers but mainly results from solid or fluid mobilization underground. Subsidence due to groundwater depletion ( 1 ) is a slow and gradual process that develops on large time scales (months to years), producing progressive loss of land elevation (centimeters to decimeters per year) typically over very large areas (tens to thousands of square kilometers) and variably affects urban and agricultural areas worldwide. Subsidence permanently reduces aquifer-system storage capacity, causes earth fissures, damages buildings and civil infrastructure, and increases flood susceptibility and risk. During the next decades, global population and economic growth will continue to increase groundwater demand and accompanying groundwater depletion ( 2 ) and, when exacerbated by droughts ( 3 ), will probably increase land subsidence occurrence and related damages or impacts. To raise awareness and inform decision-making, we evaluate potential global subsidence due to groundwater depletion, a key first step toward formulating effective land-subsidence policies that are lacking in most countries worldwide.

Science↗

USGS2019

A parametric numerical analysis of factors controlling ground ruptures caused by groundwater pumping

A modeling analysis is used to investigate the relative susceptibility of various hydrogeologic configurations to aseismic rupture generation due to deformation of aquifer systems accompanying groundwater pumping. An advanced numerical model (GEPS3D) is used to simulate rupture generation and propagation for three typical processes: (i) reactivation of a preexisting fault, (ii) differential compaction due to variations in thickness of aquifer/aquitard layers constituting the aquifer system, and (iii) tensile fracturing above a bedrock ridge that forms the base of the aquifer system. A sensitivity analysis is developed to address the relative importance of various factors, including aquifer depletion, aquifer thickness, the possible uneven distribution and depth below land surface of the aquifer/aquitard layers susceptible to aquifer-system compaction, and the height of bedrock ridges beneath the aquifer system which contributes to thinning of the aquifer system. The rupture evolution is classified in two occurrences. In one, the rupture develops at the top of the aquifer or at land surface and does not propagate. In the other, the developed rupture propagates from the aquifer top toward the land surface and/or from the land surface downward. The aquifer depth is the most important factor controlling rupture evolution. Specifically, the probability of a significant rupture propagation is higher when the aquifer top is near land surface. The numerical results are processed by a statistical regression analysis to provide a general methodology for a preliminary evaluation of possible ruptures development in exploited aquifer systems susceptible to aquifer-system compaction and accompanying land subsidence. A comparison with a few representative case studies in Arizona, USA, China, and Mexico supports the study outcomes.

Arizona↗

USGS2018

Ground ruptures attributed to groundwater overexploitation damaging Jocotepec city in Jalisco, Mexico: 2016 field excursion of IGCP-641

IGCP Project 641 (Mechanisms, Monitoring and Modeling Earth Fissure generation and Fault activation due to subsurface Fluid exploitation – M3EF3) held its second international workshop from November 2 to 6, 2016, in Puerto Vallarta and included a two-day field trip to Guadalajara and Jocotepec in the Mexican state of Jalisco (Fig. 1a). M3EF3 is aimed at i) understanding the mechanisms that cause the formation of “ground ruptures”, as a response to changes in the stress state in the subsoil, ii) monitoring their occurrence, and iii) developing appropriate approaches to model their formation and growth. Notice that many times it is difficult to discern whether a particular instance of a “ruptured” land surface is due to an earth fissure with a surface manifestation or a surface failure associated with the activation of a pre-existing fault, especially where a fault has not been mapped and where there is no obvious scarp. Therefore, in M3EF3 we preferred to use the term “ground rupture”, to refer to both such occurrences.

Jalisco↗