Global Seismic Monitoring With Real-Time GNSS

Date: 4/26/2019

Time: 09:30 AM

Room: Elliott Bay

The ongoing, global proliferation of real-time GNSS networks has blanketed many of Earth's tectonically active regions with receivers that straddle active crustal faults, tsunamigenic subduction zones, volcanoes, landslides, and many other sources of natural hazards. In some seismically active regions such as Japan and the western US, the number of GNSS receivers now rivals seismometers available for earthquake and tsunami monitoring. Steady improvements in the accuracy and stability of real-time positioning has encouraged integration of GNSS into existing monitoring and hazards mitigation systems. GNSS positions computed in real-time are now utilized by the USGS and NOAA because they offer nearly instant quantification of coseismic deformation, a direct constraint on moment magnitude, while coseismic slip unfolds. Where station density allows, real-time positions can also map the accumulation of fault slip as rupture propagates, which is particularly valuable during extended, complex earthquakes whose rupture may last minutes and span multiple fault systems. For these most damaging events, traditional seismic centroid solutions fail to accurately characterize either slip. Additionally, the delay required to obtain accurate centroids severely limits many emergency response mechanisms. Real-time GNSS offers dramatic improvements for these types of events. Improvements in real-time positioning and downstream product generation are expected to continue. The incipient launch of new constellations transmitting on distinctive frequencies will enable higher-order corrections to signal propagation delays that will result in stable, sub-centimeter real-time point positioning. The development of high-quality ancillary models required for positioning will also improve delivery and rate of adoption of new hazard mitigation products. These products include time-dependent atmospheric delay, satellite orbit and clock perturbations, and earth orientation, increasing the stability and accuracy of positioning and downstream hazard mitigation products to those who need them quickly.

Presenting Author: Walter Szeliga

Authors