Slip pulse and resonance of the Kathmandu basin during the 2015 Gorkha earthquake, Nepal.

Detailed geodetic imaging of earthquake ruptures enhances our understanding of earthquake physics and associated ground shaking. The 25 April 2015 moment magnitude 7.8 earthquake in Gorkha, Nepal was the first large continental megathrust rupture to have occurred beneath a high-rate (5-hertz) Global Positioning System (GPS) network. We used GPS and interferometric synthetic aperture radar data to model the earthquake rupture as a slip pulse ~20 kilometers in width, ~6 seconds in duration, and with a peak sliding velocity of 1.1 meters per second, which propagated toward the Kathmandu basin at ~3.3 kilometers per second over ~140 kilometers. The smooth slip onset, indicating a large (~5-meter) slip-weakening distance, caused moderate ground shaking at high frequencies (>1 hertz; peak ground acceleration, ~16% of Earth's gravity) and minimized damage to vernacular dwellings. Whole-basin resonance at a period of 4 to 5 seconds caused the collapse of tall structures, including cultural artifacts.

Influence of simultaneous exposure to acrylonitrile and styrene on the toxicity and metabolism of styrene in rats.

Nine groups of adult male rats were given different combinations of styrene and acrylonitrile and each chemical was administered at three doses (styrene 0, 5.8, and 11.6 mmol/kg, ip; acrylonitrile 0, 0.3, and 0.6 mmol/kg, po). The animals were killed 24 hr later and blood and urine samples were collected. The results of biochemical analyses due to the toxicity of both chemicals and of the determination of urinary metabolites of styrene were then subjected to a factorial (3 X 3) analysis of variance. There was: (1) a significant elevation of blood urea nitrogen (BUN) and serum glutamic-pyruvic transaminase (SGPT), and a diminution of urinary creatinine due to styrene; (2) an increase in serum creatinine and serum glutamicoxaloacetic transaminase (SGOT) due to styrene that was further increased by acrylonitrile; and (3) an increase in the concentrations of urinary metabolites (thioethers, mandelic, phenylglyoxylic, and hippuric acids) due to styrene that was considerably reduced by acrylonitrile. These results suggest that styrene causes renal toxicity which may be potentiated by acrylonitrile; furthermore, the significant diminution of the urinary metabolites of styrene due to acrylonitrile obscures interpretation of the results of the biological monitoring of exposure to styrene.