GNSS Strain Rate

Introduction

Utilizing satellite-based geodetic methods, particularly GNSS, offers a powerful means to quantify movements and alterations in the Earth's crust. The velocities of surface points obtained through geodetic techniques are crucial in examining the motion of tectonic plates, pinpointing areas of concentrated strain in active geological structures both in interplate and intraplate areas, and estimating the rheological characteristics of both the crust and the underlying asthenosphere, etc. (Dixon, 1991). Typically, these geodetic velocities and their associated uncertainties are determined indirectly via repetitive measurements of specific points.

Study Region

Our regions of study are selected based on historical and current earthquake occurrence in the NMSZ where, elastic rebound theory predicts crustal elastic strain should accumulate at a linear rate between earthquakes, and the epicentral area of the Pawnee earthquake where there may still be a small postseismic or earthquake inducing signal. 

Strain 

- Strain Analysis

Deformation is the change in shape a material undergoes in response to an applied force. Fig. 2 shows three points in an initial coordinate system X (light triangle with inscribed circle), which are displaced along three non-parallel and non-equal vectors u, to their final coordinates x (dark triangle with inscribed ellipse). 

- Trajectory Models 

The position vector of a station  can be decomposed in a local or topocentric cartesian axis system  in which the axes point east, north and up (right-handed). The standard linear trajectory model (SLTM) is a kinematic model which is the sum of four displacement modes, or distinct classes of motion, that describe the progressive trend of the trajectory, any instantaneous jumps in position because of either earthquakes or equipment changes, postseismic transitions, and periodic or cyclical displacements (Montillet and Bos 2019): . 

ES-SSA Annual MeetingEastern Section

27-28 October 2025 in St. Louis, Missouri