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Mapping out backward motion Most deformation associated with an earthquake is, not surprisingly, in the same direction as the fault rupture. Xu et al. used satellite imaging to find areas of deformation associated with the 2019 Ridgecrest earthquake sequence that moved in the opposite direction. These regions moved in this direction because of inelastic deformation, which helped to accommodate the overall fault rupture for the sequence. The observations were possible because of improved radar imaging and are likely more common than previously believed. Science , this issue p. 605

High-resolution tectonic solutions Detailed topographic maps are available for only a small fraction of the ocean floor, severely limited by the number of ship crossings. Global maps constructed using satellite-derived gravity data, in contrast, are limited in the size of features they can resolve. Sandwell et al. present a new marine gravity model that greatly improves this resolution (see the Perspective by Hwang and Chang). They identify several previously unknown tectonic features, including extinct spreading ridges in the Gulf of Mexico and numerous uncharted seamounts. Science , this issue p. 65 ; see also p. 32

A digital bathymetric map of the oceans with a horizontal resolution of 1 to 12 kilometers was derived by combining available depth soundings with high-resolution marine gravity information from the Geosat and ERS-1 spacecraft. Previous global bathymetric maps lacked features such as the 1600-kilometer-long Foundation Seamounts chain in the South Pacific. This map shows relations among the distributions of depth, sea floor area, and sea floor age that do not fit the predictions of deterministic models of subsidence due to lithosphere cooling but may be explained by a stochastic model in which randomly distributed reheating events warm the lithosphere and raise the ocean floor.

Synthetic aperture radar is a technique for mapping Earth9s surface that offers tremendous spatial resolution. In their Perspective, Meade and Sandwell report on a recent meeting at the U.S. National Academy of Sciences in which future geodetic uses of this technique were discussed.