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Very shallow M6.6 earthquake hits Ogasawara region, Japan
A very shallow earthquake registered by the JMA as M6.6 hit Japanese Ogasawara Archipelago at 18:22 UTC (03:22 JST) on August 16, 2018. The USGS is reporting M6.4 at a depth of 11.5 km (7.1 miles) at 18:21 and M6.0 at 18:22 UTC. EMSC is reporting M6.4 and M5.9 at a depth of 10 km (6.2 miles). According to the USGS, the epicenter was located 251 km (156 miles) SE of Iwo Jima, 420.9 km (261.5 miles) SSW of Ogasawara, Japan and 945.4 km (587.5 miles) NNW of Saipan, Northen Mariana Islands. There are no people living within 100 km (62 miles). Although there may be slight sea-level changes in coastal regions, this earthquake has caused no damage to Japan, JMA said. The closest volcanoes are Minami-Hiyoshi and Nikko, both submarine. They have located roughly 100 km (62 miles) W of the epicenter. Periodic water discoloration and water-spouting have been reported over Minami-Hiyoshi since 1975 when detonations and an explosion were als…

ELECTRIC-BLUE CLOUDS CIRCLING ANTARCTICA


NASA's AIM spacecraft is monitoring a vast ring of electric-blue clouds circling high above Antarctica.  These are noctilucent clouds (NLCs), made of ice crystals frosting specks of "meteor smoke" in the mesosphere 83 km above the frozen continent. Here is an animation from the past week:

This is the season for southern noctilucent clouds. Every year around this time, summertime water vapor billows up into the high atmosphere over Antarctica, providing the moisture needed to form icy clouds at the edge of space.  Sunlight shining through the high clouds produces an electric-blue glow, which AIM can observe from Earth orbit.
"The current season began on Nov. 19th," says Cora Randall, a member of the AIM science team at the University of Colorado's Laboratory for Atmospheric and Space Physics. "Compared to previous years of AIM data, this season seems to be fairly average, but of course one never knows what surprises lie ahead, particularly since the southern hemisphere seasons are so variable."
The formation of strange clouds in the high atmosphere over remote Antarctica may seem to be of little practical interest--but that would be incorrect. Researchers studying NLCs have discovered unexpected teleconnections between these clouds and weather patterns thousands of miles away. Two years ago, for instance, Randall and colleagues found that the winter air temperature in many northern US cities was well correlated with the frequency of noctilucent clouds over Antarctica. Understanding how these long-distance connections work could improve climate models and weather forecasting--all the more reason to study eerily beautiful NLCs.

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