Archive for April, 2015

Nepal, April 2015: Magnitude 7.8 Main Shock and Magnitude 6.7 Aftershock

April 28, 2015

We actually do still record the old-style “paper on a rotating drum” seismograms at Weston Observatory.

Note, however, how much higher-quality the modern digital recordings are (see below). This makes it possible to learn much, much more about the earthquakes than we used to be able to.

Nepal_042515_WWSSN

Weston_Drums

Nepal_042515_Main_After

USGS Tectonic Summary
2015-04-26 07:09:10 (UTC)
19km (12mi) SSE of Kodari, Nepal
Magnitude 6.7
27.782°N
85.997°E
depth=17.3 km (10.7 mi)

Magnitude 7.8 – 34km ESE of Lamjung, Nepal – April 25, 2015

April 25, 2015

NepalUSGS: “Seismicity in the Himalaya dominantly results from the continental collision of the India and Eurasia plates, which are converging at a relative rate of 40-50 mm/yr. Northward underthrusting of India beneath Eurasia generates numerous earthquakes and consequently makes this area one of the most seismically hazardous regions on Earth.”

USGS Tectonic Summary
2015-04-25 06:11:26 (UTC)
Magnitude 7.8
34km (21mi) ESE of Lamjung, Nepal
28.147°N 84.708°E depth=15.0 km (9.3 mi)

Magnitude 6.2 – 182km WSW of Bella Bella, Canada – April 24, 2015

April 24, 2015

MLMA NEMAUSGS Tectonic Summary
2015-04-24 13:56:16 (UTC)
182km (113mi) WSW of Bella Bella, Canada
51.769°N   -130.695°W
depth=10 km (6.2 mi)