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Very strong M7.3 earthquake hits Venezuela at intermediate depth
A very strong earthquake registered by the USGS as M7.3 hit near the coast of Sucre, Venezuela at 21:31 UTC on August 21, 2018. The agency is reporting a depth of 123.2 km (76.5 km). EMSC is reporting M7.3 at a depth of 112 km (69.6 miles). According to the USGS, the epicenter was located  20.9 km (13.0 miles) NNW of Yaguaraparo, 38.4 km (23.9 miles) ENE of Carúpano (population 112 082), 69.4 km (43.1 miles) WNW of Güiria (population 40 000), 107.6 km (66.9 miles) ESE Porlamar (population 87 120) and 109.1 km (67.8 miles) ESE of La Asunción (population  35 084), Venezuela. There are 560 000 people living within 100 km (62 miles). Based on all available data, there is no tsunami threat, PTWC said. Some 52 000 people are estimated to have felt very strong shaking, 2 089 000 strong, 2 587 000 moderate and 3 928 000 light. Buildings were evacuated in the capital Caracas and people fled homes. Shaking was felt as far away as …

Remarkable pink aurora outburst over Norway


Remarkable pink aurora outburst over Norway

Over the past couple winters, big displays of pink and white auroras have coincided with spotless suns. The sight is often big enough to make observers wonder if there is a connection, SpaceWeather reports.
The most recent remarkable outburst of pink auroras was observed on November 22, 2017, from Tromsø, Norway. "Suddenly, the whole valley turned white (with a hint of pink)," says Frank Meissner, who witnessed and photographed the display. "It was over after about 20 seconds," he said.
"The brightness can be compared to the car-lights in the background," Meissner added.
Pink aurora over Tromso, Norway on November 22, 2017
Pink aurora over Tromsø, Norway on November 22, 2017. Credit: Frank Meissner (via SpaceWeather)
An even more dramatic display was witnessed in nearby Kvaløya and captured by aurora guide Marianne Bergli who said their guests stopped taking pictures. "They were struck with awe and froze at the wonderful display."
White and pink aurora at Kvaloya, Norway on November 22, 2017
White and pink aurora at Kvaløya, Norway on November 22, 2017. Credit: ChaseTheLightTours (via SpaceWeather)
"The pink color of the outburst tells us something interesting about the solar wind on November 22nd: it seems to have been unusually penetrating," Dr. Tony Phillips of said. 
The colors of the aurora are determined by the composition of gases in the Earth's atmosphere, the altitude at which the aurora occurs, the density of the atmosphere, and the level of energy involved. Green, the most common color seen from the ground, is produced when charged particles collide with oxygen at lower altitudes (around 100 - 300 km / 62 - 186 miles).
Occasionally, the lower edge of an aurora will have a pink or crimson fringe, which is produced by nitrogen molecules (around 100 km / 62 miles).
Higher in the atmosphere (300 - 400 km / 186 - 250 miles), collisions with atomic oxygen produce red instead of green. Since the atmosphere is less dense at higher altitudes, it takes more energy and more time to produce red light (up to two minutes), whereas green light can be made quickly at lower altitudes (about one second).
Hydrogen and helium can also produce blue and purple, but those colors tend to be difficult for our eyes to see the night sky.
"In recent winters, big displays of pink and white auroras have coincided with spotless suns often enough to make observers wonder if there is a connection. If so, more outbursts are in the offing as the Sun continues its plunge toward a deep Solar Minimum," Phillips concluded.
Featured image: Pink aurora over Tromsø, Norway on November 22, 2017. Credit: Frank Meissner (via SpaceWeather)

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