Earthquake Swarm on Alaska’s North Slope


OK, the ground up there isn’t jumping so much it knocks down polar bears–this is just a laid-back local resident.

But a magnitude 6.4 quake is unusual on Alaska’s Arctic Ocean coast, and no one really knows what caused the Sunday event.

They call this region the North “Slope,” not the North “Trench,” because it’s not a subduction zone like the Aleutian Islands, where megathrust quakes are possible. There’s a lot of petroleum down there, and at the surface it is a national wildlife refuge. Apparently there is no drilling ongoing at the epicenter site, near an Inuit village called Kaktovic.

The Sunday quake was part of an ongoing swarm. There were a few events in the magnitude-6 range, with the 6.4 being the largest ever recorded up there. The rest are M3 or lower, and it’s still quite active up there along the Arctic Ocean today.



Nothing dire seems imminent, but it is unusual and worth noting. There hasn’t been much in the news, just this Arctic Today article (you’ll have to give them an email address to read it – sorry, but there are no alternative news sources) and this Alaska Earthquake Center post, which links to their continuously updated data pages. They’re really excited about it because they happened to have a dense array of seismometry equipment in place and now have a lot of data about the region’s geology, which isn’t well understood yet.


August 17, 2018: Here’s how last Sunday’s event looked as it travelled through that seismometer array that happens to be set up across Alaska at present.


August 22, 2018: Nothing much new in the news, though reportedly the petroleum people in the region did a flurry of inspections and found no equipment problems after the August 12th quake. The general epicenter area is still having lots of very low-level activity per today’s “latest earthquakes” USGS website (am guessing it’s the regional stress field adjusting to whatever rock formations “broke” down there).


September 18, 2018: An M5.1 in the general region of Kaktovik today. However, per the Alaska Earthquake Center event page, this may be related more to the Brooks Range than to the bigger August event on the North Slope.

Alaska’s geology is very complicated, even far from the Aleutian subduction zone.


Featured image: Alaska Region US Fish & Wildlife Service


Advertisements

Guest Videos: Mikhail Lomonosov


You might run across the word “Lomonosov” in the news soon. A ridge of that name is a big part of Russia’s claim to the Arctic, and the UN committee that is responsible for deciding such territorial claims just began a new session.

This ridge is named after a famous 18th-century Russian polymath–Mikhail Lomonosov–who, among other things, discovered in 1761 that the planet Venus has an atmosphere.

Unfortunately, there isn’t much about him in English online other than Wikipedia and the usual science biography sites on YouTube.



However, Lomonosov is worth checking out today for two reasons.

First, during the 1970s, the Russians followed up spectacularly on that initial Venus discovery.



Second, tomorrow’s Sunday Morning Volcano sits very close to the Lomonosov Ridge.

To be continued . . .


Featured image: The 2012 transit of Venus, NASA/SDO, AIA via Wikimedia, CC BY-SA 2.0/Portrait of M. Lomonosov, Russian Academy of Sciences via Wikimedia.



Sources:

Lomonosov, M., and Shiltsev, V. 2018. Mikhail Lomonosov. Meditations on Solidity and Fluidity of Bodies (1760). English translation and commentary by V. Shiltsev. arXiv preprint arXiv:1801.00909 (PDF).

Marov, M. Y. 2004. Mikhail Lomonosov and the discovery of the atmosphere of Venus during the 1761 transit. Proceedings of the International Astronomical Union, 2004(IAUC196), 209-219.