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The Mw 6.4 and Mw 7.1 Ridgecrest earthquake sequence occurred on 4 and 5 July 2019 within the eastern California shear zone of southern California. Both events produced extensive surface faulting and ground deformation within Indian Wells Valley and Searles Valley. In the weeks following the earthquakes, more than six dozen scientists from government, academia, and the private sector carefully documented the surface faulting and ground-deformation features. As of December 2019, we have compiled a total of more than 6000 ground observations; approximately 1500 of these simply note the presence or absence of fault rupture or ground failure, but the remainder include detailed descriptions and other documentation, including tens of thousands of photographs. More than 1100 of these observations also include quantitative field measurements of displacement sense and magnitude. These field observations were supplemented by mapping of fault rupture and ground-deformation features directly in the field as well as by interpreting the location and extent of surface faulting and ground deformation from optical imagery and geodetic image products. We identified greater than 68 km of fault rupture produced by both earthquakes as well as numerous sites of ground deformation resulting from liquefaction or slope failure. These observations comprise a dataset that is fundamental to understanding the processes that controlled this earthquake sequence and for improving earthquake hazard estimates in the region. This article documents the types of data collected during postearthquake field investigations, the compilation effort, and the digital data products resulting from these efforts.

The partnership between science and the environment in service-learning projects helps students to make greater connections to the world around them. Service learning provides many benefits to students, faculty, and communities within the context of a college course. However, to prevent frustration, it is important for faculty members to make a clear distinction between service learning and volunteerism by connecting their course objectives to the service being provided. They also must develop a framework for planning, assessment, and reflection. Finally, a successful partnership must be developed. Clearly defining the community setting to be used for the service-learning project will ensure a more positive outcome. Developing the partnership framework through purposeful communication with all partners is the key to successful service-learning projects. A sequential series of steps are provided for the framework development. Actual examples of classroom projects are described, along with benefits to students, agencies, and community participants.

Large-scale motions and strain-rates over great distances on polar ice sheets are often obtained from the tracking of Transit (or doppler) satellites. The results of different processing techniques for these tracking data are compared, using some of the data collected on and near Ice Stream C. Reduction is made by using the software packages CALIPER, GEODOP V, MAGNET, and the micro-processor on the Magnavox MX 1502 satellite receiver. The orbital data broadcast by the satellites are used, as well as more precise orbits obtained afterward. In addition, calculations are made for single sites individually (point positioning) and for many sites with simultaneous tracking data (network adjustment). The results agree within the range of known errors associated with the orbits. Earth-based positions (latitude, longitude, ellipsoidal height), based on the broadcast orbits, agree to within 41.1 m. Positions with more precise orbits are within 0.7 m of one another. Relative positions are best obtained by using network techniques, and these agree with terrestrial survey results within 0.2 m in horizontal separation for sites 19 km apart, and are within 4.8 m in elevation difference. The calculated azimuth differs by 1.5 m/19 km or 10−4 rad.

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