A concept has been developed for a geostationary seismic imager (GSI), a space telescope in geostationary orbit above the Pacific coast of the Americas that would provide movies of many large earthquakes occurring in the area from Southern Chile to Southern Alaska. The GSI movies would cover a field of view as long as 300 km, at a spatial resolution of 3 to 15 m and a temporal resolution of 1 to 2 Hz, which is sufficient for accurate measurement of surface displacements and photometric changes induced by seismic waves. Computer processing of the movie images would exploit these dynamic changes to accurately measure the rapidly evolving surface waves and surface ruptures as they happen. These measurements would provide key information to advance the understanding of the mechanisms governing earthquake ruptures, and the propagation and arrest of damaging seismic waves.
GSI operational strategy is to react to earthquakes detected by ground seismometers, slewing the satellite to point at the epicenters of earthquakes above a certain magnitude. Some of these earthquakes will be foreshocks of larger earthquakes; these will be observed, as the spacecraft would have been pointed in the right direction. This strategy was tested against the historical record for the Pacific coast of the Americas, from 1973 until the present. Based on the seismicity recorded during this time period, a GSI mission with a lifetime of 10 years could have been in position to observe at least 13 (22 on average) earthquakes of magnitude larger than 6, and at least one (2 on average) earthquake of magnitude larger than 7.
A GSI would provide data unprecedented in its extent and temporal and spatial resolution. It would provide this data for some of the world’s most seismically active regions, and do so better and at a lower cost than could be done with groundbased instrumentation. A GSI would revolutionize the understanding of earthquake dynamics, perhaps leading ultimately to effective warning capabilities, to improved management of earthquake risk, and to improved public safety policies.
The position of the spacecraft, its high optical quality, large field of view, and large field of regard will make it an ideal platform for other scientific studies. The same data could be simply reused for other studies. If different data, such as multi-spectral data, is required, additional instruments could share the telescope.
This work was done by Erkin Sidick, Keith Coste, Thomas J. Cunningham, Michael W. Sievers, Gregory S. Agnes, Otto R. Polanco, Joseph J. Green, Bruce A. Cameron, David C. Redding, Jean Philippe Avouac, Jean Paul Ampuero, and Sebastien Leprince of Caltech; Rémi Michel of the Université Pierre et Marie Curie; and Jesse Redding of UC Berkeley for NASA’s Jet Propulsion Laboratory. NPO-48469
This Brief includes a Technical Support Package (TSP).
Seismic Imager Space Telescope
(reference NPO-48469) is currently available for download from the TSP library.
Don't have an account?
Overview
The document outlines the development of a Geostationary Seismic Imager (GSI), a proposed space telescope designed to capture high-quality, large-field "movies" of earthquakes from geostationary orbit. The GSI aims to provide detailed measurements of the Earth's surface motion during seismic events, with a focus on improving our understanding of earthquake dynamics and enhancing public safety.
The primary objective of the GSI is to visualize the three-dimensional motion of the Earth’s surface and subsurface during large earthquakes. It is intended to operate at a frame rate of 2 frames per second, covering a field of view of up to 300 by 300 kilometers. This capability would allow for the accurate measurement of the velocity field of the Earth's surface, capturing the shortest wavelengths of surface motion, typically between 300 to 1,000 meters.
The document highlights the collaboration with Caltech scientists to develop the scientific and engineering case for the GSI. It emphasizes the need for advanced technologies, including large-format focal plane arrays (FPAs) and robust avionics capable of handling the vast amounts of data generated during seismic events. The GSI is expected to utilize either a mosaic of small arrays or four 1-gigapixel wafer-scale arrays, with the latter being favored for its simplicity and cost-effectiveness.
Key scientific objectives of the GSI include revealing the seismic rupture process, understanding factors that influence near-field ground shaking, and monitoring a significant portion of the world’s seismically active regions more effectively and economically than traditional ground-based instrumentation. The GSI could revolutionize earthquake seismology by providing unique insights into seismic events, potentially leading to improved earthquake risk management and public safety policies.
The document also discusses the financial and technological requirements for the GSI project, indicating that some technology development will be necessary beyond what is currently available. The ultimate goal is to prepare a compelling whitepaper for submission to the next Earth Science Decadal Survey, outlining the mission concept and its potential benefits.
In summary, the GSI represents a significant advancement in seismic monitoring technology, with the potential to transform our understanding of earthquakes and enhance disaster preparedness and response efforts globally.
