Loading‐Induced Earth's Stress Change Over Time

Abstract

We establish a physical framework and build a preliminary database of stress changes on the Earth from 2000 to 2017 in a global scale and at various depths. We consider six loading forces that would generate stress changes on the Earth: hydrological loading, atmospheric pressure, ocean water (including tides and nontidal variation), solid lunisolar tides, pole tide, and postglacial rebound (PGR). The maximum amplitudes of normal deviatoric stress changes on the Earth's surface caused by hydrological loading, atmospheric pressure, and solid lunisolar tides reach 10 À2 bar, those by pole tide 10 À4 -10 À3 bar, and those by ocean tides 10 À1 bar mostly in the coastal regions. The shear stress changes are about 1 order of magnitude smaller than the normal deviatoric stresses. The PGR-induced stress rates are 10 À3 -10 À2 bar/year. Stress variations caused by the different forces also exhibit different spatial patterns, with large hydro-induced stresses mainly distributed in torrid and frigid zones, atmosphere-induced stresses in temperate and frigid zones, and ocean-induced stresses in coastlands and PGR-induced stress rates in Greenland, north Europe, North America, and Antarctica. The hydro-induced stresses exhibit significant seasonal variations in Amazon Basin, northern India, and central Africa and persistent increase/decrease in Antarctica, Greenland, and Alaska due to ice shelf melting. All loading-induced stress changes exhibit significant depth variations. The stress database would provide a resource for better understanding the triggering mechanisms of various tectonic events, and the physical framework we establish to build the database could be useful for better studying properties and physical states of Earth's interior.

Strong Hydro‐Related Localized Long‐Period Crustal Deformation Observed in the Plate Boundary Observatory Borehole Strainmeters

“…Correspondence to: Z. Lu, luzhou@mail.ustc.edu.cn Citation: Lu, Z., & Wen, L. (2018). Strong hydro-related localized long-period crustal deformation observed in the Plate Boundary Observatory borehole strainmeters.…”

“…Wang & Barbour, ). Stress changes related to hydrological process are also recognized to be significant (e.g., Johnson et al, ; Lu et al, ), and may have triggered and/or modulated many tectonic events, including earthquakes (Amos et al, ; Craig et al, ; Johnson et al, ), slow slip events (Frank et al, ), and tremors (Thomas et al, ).…”

“…Wang & Barbour, 2017). Stress changes related to hydrological process are also recognized to be significant (e.g., Johnson et al, 2017b;Lu et al, 2018), and may have triggered and/or modulated many tectonic events, including earthquakes (Amos et al, 2014;Craig et al, 2017;Johnson et al, 2017a), slow slip events (Frank et al, 2015), and tremors (Thomas et al, 2009). In this study, to better understand how hydrological process produces crustal deformation, we search potential hydro-related strain signals from the recordings of the Plate Boundary Observatory (PBO) borehole strainmeters in Southern California and explore the physical mechanism through establishing poroelastic models that relate those strain signals to other hydrological observations in the region, including pore pressure and rainfall.…”

Analytical Prediction of Seismicity Rate Due to Tides and Other Oscillating Stresses

“…The study of the seismicity response to such stress variations can in principle provide insight into fault friction and earthquake nucleation mechanisms (e.g., Ader et al, 2014; Beeler & Lockner, 2003; Luo & Liu, 2019; Scholz et al, 2019) and possibly inform us of the preparatory phase to impending earthquakes (e.g., Chanard et al, 2019; Tanaka, 2012). Stresses from oscillatory loading are often temporally complex but can be computed with reasonable accuracy (e.g., Agnew, 1997; Johnson et al, 2020; Lu et al, 2018; Tanaka et al, 2015; Tsuruoka et al, 1995), and their relationship to changes in seismicity or tremor rate might reveal fundamental insight into earthquake triggering. On Mars and the Moon, such factors might be the dominant source of seismicity (Duennebier & Sutton, 1974; Lognonne, 2005; Manga et al, 2019).…”

Rupture Of Veined Granite In Polyaxial Compression: Insights From Three‐Dimensional Discrete Element Method Modeling

“…Despite the above contributions, their investigations are limited to relatively simple stress conditions. In reality, rock behaves differently under polyaxial confinement, the magnitude and orientation of which can be affected by many factors such as tectonic activities (Huang et al, 2016;Scholz, 2015), hydrological loading (Lu et al, 2018), and anthropogenic activities (Segall & Lu, 2015;Siren et al, 2015). The stress state in the three-dimensional space is generally represented by three mutually perpendicular principal stress components (i.e., σ 1 , σ 2 , and σ 3 ), where σ 1 represents the maximum principal stress, σ 2 the intermediate principal stress, and σ 3 the least principal stress (the stress is positive in compression and negative in tension).…”