Geomorphic and geologic controls of geohazards induced by Nepal's 2015 Gorkha earthquake.

The Gorkha earthquake (magnitude 7.8) on 25 April 2015 and later aftershocks struck South Asia, killing ~9000 people and damaging a large region. Supported by a large campaign of responsive satellite data acquisitions over the earthquake disaster zone, our team undertook a satellite image survey of the earthquakes' induced geohazards in Nepal and China and an assessment of the geomorphic, tectonic, and lithologic controls on quake-induced landslides. Timely analysis and communication aided response and recovery and informed decision-makers. We mapped 4312 coseismic and postseismic landslides. We also surveyed 491 glacier lakes for earthquake damage but found only nine landslide-impacted lakes and no visible satellite evidence of outbursts. Landslide densities correlate with slope, peak ground acceleration, surface downdrop, and specific metamorphic lithologies and large plutonic intrusions.

Uncertainties in the use of periodate oxidation for determination of dextran structure.

A glucan of high molecular weight isolated from stale sugar-cane, and previously shown to have a marked effect on sucrose crystallisation processes-1, is a relatively linear dextran. Approximately 96-97% of its D-glucose residues are involved in (1 yields 6)-alpha-D linkages and constitute the linear backbone of the polymer. The remaining 3-4% of D-glucose residues form branch-points by (1 yields 3)-alpha-D linkages. The periodate-oxidation technique, which has been extensively used by other workers to determine dextran structure, gave erroneous results when applied to the dextran from stale sugar-cane.