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Abstract The Alpine‐Himalayan belt is one of Earth's most dynamic and complex regions, characterized by intense tectonic deformation and seismicity. Comprehensive analyses of continental‐scale crustal deformation and seismic hazards along this extensive orogenic belt require the compilation of large geodetic data sets. In this study, we integrate 42 published Global Navigation Satellite System (GNSS) velocity fields, building an internally consistent data set for the entire belt, spanning from Iberia to Southeast Asia and comprising 11,177 horizontal and 3,940 vertical velocities. We use this unified GNSS velocity field to estimate surface strain rates and their posterior uncertainties in the eastern Mediterranean region and the India‐Asia collision zone. Our results show large‐scale agreement between the orientation and style of geodetic and seismic strain rate tensors across the belt. Additionally, our analyses substantiate previously documented azimuthal alignments between principal strain rate directions and seismic anisotropy orientations, often used as a proxy for finite strain in the convecting mantle. These correlations are particularly apparent in the Aegean, North Anatolia, Tibet, Tian Shan, Altai, Sayan, and Baikal regions, underscoring the need for future research on the relationship between mantle flow and lithospheric deformation. 

Abstract Interseismic coupling maps and, especially, estimates of the location of the fully coupled (locked) zone relative to the trench, coastline, and slow slip events are crucial for determining megathrust earthquake hazard at subduction zones. We present an interseismic coupling inversion that estimates the locations of the upper and lower boundaries of the locked zone, the lower boundary of the deep transition zone, and downdip gradient of creep rate in the transition from locked to freely creeping in the downdip transition zone. We show that the locked zone at Cascadia is west of the coastline and 10 km updip of the slow slip zone along much of the margin, widest (25–125 km, extending to ∼19 km depth) in northern Cascadia, narrowest (0–70 km) in central Cascadia, with moment accumulation rate equivalent to a M_w8.71 and M_w8.85 earthquake for 300‐ and 500‐year earthquake cycles. We find a steep gradient in creep immediately below the locked zone, indicative of propagating creep, along the entire margin. At Nankai, we find three distinct zones of locking (offshore Shikoku, offshore southeast Kii peninsula, and offshore Shima peninsula) with a total moment accumulation rate equivalent to a M_w8.70 earthquake for a 150‐year earthquake cycle. The bottom of the locked zone is nearly under the coastline for all three locked regions at Nankai and is positioned 0–5 km updip of the slow slip zone. In contrast with Cascadia, creep rate gradients below the locked zone at Nankai are generally gradual, consistent with stationary locking. 

Motor vehicles are among the major sources of pollutants and greenhouse gases in urban areas and a transition to “zero emission vehicles” is underway worldwide. However, emissions associated with brake and tire wear will remain. We show here that previously unrecognized volatile and semi-volatile organic compounds, which have a similarity to biomass burning emissions are emitted during braking. These include greenhouse gases or, these classified as Hazardous Air Pollutants, as well as nitrogencontaining organics, nitrogen oxides and ammonia. The distribution and reactivity of these gaseous emissions are such that they can react in air to form ozone and other secondary pollutants with adverse health and climate consequences. Some of the compounds may prove to be unique markers of brake emissions. At higher temperatures, nucleation and growth of nanoparticles is also observed. Regions with high traffic, which are often disadvantaged communities, as well as commuters can be impacted by these emissions even after combustion-powered vehicles are phased out. 

Abstract The structure of the critical zone (CZ) is a product of feedbacks among hydrologic, climatic, biotic, and chemical processes. Past research within snow‐dominated systems has shown that aspect‐dependent solar radiation inputs can produce striking differences in vegetation composition, topography, and soil depth between opposing hillslopes. However, far fewer studies have evaluated the role of microclimates on CZ development within rain‐dominated systems, especially below the soil and into weathered bedrock. To address this need, we characterized the CZ of a north‐facing and south‐facing slope within a first‐order headwater catchment located in central coast California. We combined terrain analysis of vegetation distribution and topography with soil pit characterization, geophysical surveys and hydrologic measurements between slope‐aspects. We documented denser vegetation and higher shallow soil moisture on north facing slopes, which matched previously documented observations in snow‐dominated sites. However, average topographic gradients were 24° and saprolite thickness was approximately 6 m across both hillslopes, which did not match common observations from the literature that showed widespread asymmetry in snow‐dominated systems. These results suggest that dominant processes for CZ evolution are not necessarily transferable across regions. Thus, there is a continued need to expand CZ research, especially in rain‐dominated and water‐limited systems. Here, we present two non‐exclusive mechanistic hypotheses that may explain these unexpected similarities in slope and saprolite thickness between hillslopes with opposing aspects. 

Building on the successful Argo network of seafaring temperature and salinity sensors, work is underway to deploy 1,000 floats equipped to study ocean biogeochemistry in greater detail than ever.