Nepal's quake-driven landslide hazards Large earthquakes can trigger dangerous landslides across a wide geographic region. The 2015 M w 7.8 Gorhka earthquake near Kathmandu, Nepal, was no exception. Kargal et al. used remote observations to compile a massive catalog of triggered debris flows. The satellite-based observations came from a rapid response team assisting the disaster relief effort. Schwanghart et al. show that Kathmandu escaped the historically catastrophic landslides associated with earthquakes in 1100, 1255, and 1344 C.E. near Nepal's second largest city, Pokhara. These two studies underscore the importance of determining slope stability in mountainous, earthquake-prone regions. Science , this issue p. 10.1126/science.aac8353 ; see also p. 147

Subsidence is a common cause of amplifi ed relative sea-level rise, fl ooding, and erosion in coastal environments. In particular, subsidence due to sediment consolidation can play a signifi cant role in relative sea-level rise in large deltas. We use a combination of InSAR (interferometric synthetic aperture radar), leveling, and global positioning system data to map absolute vertical land motion in the Fraser River delta, western Canada. We show that primary consolidation of shallow Holocene sediments is the main cause for the slow subsidence (−1 to −2 mm/a) affecting the delta lowlands. In addition, parts of the delta undergo increased anthropogenic subsidence. Rapid subsidence rates (−3 to −8 mm/a) are associated with recent artifi cial loads and exhibit a fi rst-order exponential decrease with a time constant of ~20 years, consistent with the theory of consolidation. Assuming two sea-level rise scenarios of 30 or 100 cm by the end of the twenty-fi rst century, natural subsidence will augment relative sea-level rise in the Fraser Holocene lowlands by ~50% or ~15%. Anthropogenic subsidence will augment relative sea-level rise by ~130% or ~40%, potentially raising it to as much as 1-2 m. In deltaic, lacustrine, and alluvial environments, anthropogenic sediment consolidation can result in signifi cant amplifi cation and strong spatial variations of relative sea-level rise that need to be considered in local planning.

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BackgroundSeven male Labrador Retriever puppies from 3 different litters, born to clinically normal dams and sires, were evaluated for progressive weakness and muscle atrophy. Muscle biopsies identified a congenital myopathy with pathologic features consistent with myotubular myopathy. Further investigations identified a pathogenic mutation in the myotubularin gene, confirming that these puppies had X‐linked myotubular myopathy (XLMTM).ObjectiveTo review the clinical phenotype, electrodiagnostic and laboratory features of XLMTM in this cohort of Labrador Retrievers.ResultsMale puppies with XLMTM were small and thin compared with their normal littermates. Generalized weakness and muscle atrophy were present by 7 weeks of age in some puppies and evident to most owners by 14 weeks of age. Affected puppies stood with an arched spine and low head carriage, and walked with a short, choppy stride. Muscle atrophy was severe and progressive. Patellar reflexes were absent. Laryngeal and esophageal dysfunction, and weakness of the masticatory muscles occurred in puppies surviving beyond 4 months of age. Serum creatine kinase activity was normal or only mildly increased. EMG findings were nonspecific and included positive sharp waves and fibrillation potentials. Clinical signs progressed rapidly, with most affected puppies unable to walk within 3–4 weeks after clinical signs were first noticed.Conclusions and Clinical ImportanceAlthough initial clinical signs of XLMTM are similar to the phenotypically milder centronuclear myopathy in Labrador Retrievers, XLMTM is a rapidly progressive and fatal myopathy. Clinicians should be aware of these 2 distinct myopathies with similar clinical presentations in the Labrador retriever breed.

Synthetic aperture radar (SAR) data have been identified as a potential source of information for monitoring surface water, including open water and flooded vegetation, in frequent time intervals, which is very significant for flood mapping applications. The SAR specular reflectance separates open water and land surface, and its canopy penetration capability allows enhanced backscatter from flooded vegetation. Further, under certain conditions, the SAR signal from flooded vegetation may remain coherent between two acquisitions, which can be exploited using the InSAR technique. With these SAR capabilities in mind, this study examines the use of multi-temporal RADARSAT-2 C band SAR intensity and coherence components to monitor wetland extent, inundation and vegetation of a tropical wetland, such as Amazon lowland. For this study, 22 multi-temporal RADARSAT-2 images (21 pairs) were used for InSAR processing and the pairs in the low water stage (November, December) showed high coherence over the wetland areas. The three-year intensity stack was used for assessing wetland boundary, inundation extent, flood pulse, hydroperiod, and wetland vegetation. In addition to the intensity, derived coherence was used for classifying wetland vegetation. Wetland vegetation types were successfully classified with 86% accuracy using the statistical parameters derived from the multi-temporal intensity and coherence data stacks. We have found that in addition to SAR intensity, coherence provided information about wetland vegetation. In the next year, the Canadian RADARSAT Constellation Mission (RCM), will provide more data with frequent revisits, enhancing the application of SAR intensity and coherence for monitoring these types of wetlands at large scales.

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We use two independent methods to map the spatial variations in vertical motion of the land surface in the Greater Vancouver Regional District: 1) first-order geodetic levelling in 1958/1959 and 1977, and 2) satellite-based Coherent-Target-Monitoring Interferometric-Synthetic-Aperture RADAR (CTM-InSAR) over the period 1992-1999. The first-order geodetic levelling involves over 60 benchmarks and the CTM-InSAR over 300,000 ground targets. Vertical velocities at five permanent Global Positioning System sites, together with 37 other sites in British Columbia and Washington, are used to align the levelling and CTMInSAR results to the ITRF2000 global reference frame. The combined analysis shows an average subsidence rate in the Holocene delta (Richmond and Delta municipalities) of 1-2 mm/yr compared to uplift of 0-1 mm/yr in the Pleistocene Highlands (Vancouver, Burnaby, Surrey, Tsawwassen Heights). Areas of subsidence coincide with recent (post-glacial) Fraser River Delta sedimentation but there is no significant correlation with known variations in sediment thickness. Localized rapid subsidence areas (> 4 mm/yr) appear to be associated with sites of relatively recent construction. The BC Ferries Terminal at Tsawwassen, for which historical levelling data and CTM-InSAR are available, exhibits subsidence rates that have diminished from 15 mm/yr in the 1960's and 1970's to 3 mm/yr in the 1990's. More work is needed to determine the effects of the age and size of engineering structures on the observed vertical velocities. The land subsidence map is tied to regional sea level using a subset of collocated tide gauges and GPS stations. This analysis points to a regional Northeast Pacific sea-level rise of 1.8 mm/yr over the 20th century. In contrast, the local tide gauges at Point Atkinson and Vancouver show a low regional sea-level rise of 0.3 mm/yr when combined with our geodetic results. We conclude that the two local gauges are problematic and should not be used for sea-level rise analysis, unless a physical reason for the low rates can be found. Based on the Intergovernmental Panel on Climate Change global predictions, we estimate a future relative sea-level rise (sea-level increase + subsidence) by 2100 of 40-70 cm for most of the Fraser River Delta, and possibly as much as 130 cm in areas that are subsiding rapidly.