Measurements of surface deformation after an earthquake can be used to probe the frictional properties of the earthquake fault and the rheological properties of the crust and upper mantle. Large magnitude earthquakes (approximately M > 7) can stress deeper parts of the Earth's crust and upper mantle; their postseismic motions likely reflect a range of processes and properties, including afterslip, viscous relaxation of the lower crust and/or upper mantle, and poroelastic effects. In contrast, stress changes associated with smaller magnitude events may only affect the upper and middle crust and may exhibit a more limited range of postseismic phenomena. Whether a deformation process is active or not likely depends in part on stress change magnitude. Studying postseismic responses for a range of earthquake magnitudes is therefore important.Until recently, studies of the postseismic response of smaller magnitude earthquakes were challenged by low signal to noise ratios. However, improvement in geodetic techniques, such as GPS and InSAR, now permits such studies. Here, we present geodetic and seismic data covering the first 7 months after the 15 May 2020, M w 6.5 Monte Cristo Range (MCR), Nevada, earthquake. Combined seismic and geodetic data suggest that aseismic afterslip on the main fault plane dominates the postseismic response. We focus on three questions:1. What is the ratio of seismic to aseismic afterslip? 2. How is postseismic slip distribution related to coseismic slip and surface rupture? 3. Does afterslip reduce the shallow slip deficit (difference between surface slip and slip at depth)?
<p>The use of unoccupied aerial systems (UAS) in geoscience has dramatically improved our ability to collect data at high resolution, minimal cost, and in rapid response to sudden events. The wide range of sensor and platform configurations gives scientists great flexibility in survey design and data collection. Satellite remote sensing data has exceptional spatial coverage and continues to increase its data acquisition to meter-level resolution. UAS data can image to the cm-level resolution but lacks the same spatial coverage as satellite. By combining and comparing UAS data with satellite and ground-based remote sensing data we can utilize the different strengths of these systems. Here we demonstrate various UAS applications in high-resolution topographic change, land use classification, and sub-surface geological mapping. We use UAS payloads such as RTK georeferenced RGB and multispectral images, lidar, and magnetic sensors to image surface changes and sub-surface structures. We demonstrate the need for post-processing (PPK) high precision GNSS rover locations over utilizing only RTK position information.</p><p>Florida, USA, is home to rapidly changing beaches and wetlands, which are highly susceptible to our changing climate and destructive storm events. We show examples from beaches and wetlands in Pinellas County, Florida, USA where we have a) imaged the emergence and development of a barrier island, b) developed automated land use classification using photogrammetry and multispectral data, c) evaluated the impacts of a major hurricane event on a recently renourished beach. Pacaya Volcano, Guatemala, is an active volcano with frequent lava flows and historical flank collapse events. Using a combination of satellite DEMs, ground-based Terrestrial Radar Interferometry data, and UAS RGB SfM-photogrammetry, we have imaged recent lava flows in high-resolution showing details of lava flow levees and other structures. By comparing our data to pre-eruption satellite DEMs we can evaluate the volume and morphology of recently emplaced lava flows. In addition, we have collected magnetic data over recent lava flows that allows us to image the sub-surface structure of the lava flows and model lava flow properties. UASs are a powerful tool for remote sensing, geodetic, and geophysical data collection. They augment satellite and ground-based methodologies and by combining multidisciplinary data from these platforms we can image the earth in greater spatial and temporal detail than ever before. &#160;</p>
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