Canadian Arctic Archipelago Hit By M5.8 Earthquake

An earthquake with a magnitude of 5.8 on the Richter scale hit the Canadian Arctic Archipelago on January 8, 2017.

Above image was created with USGS (United States Geological Survey) content. The image shows the epicenter of the quake (gold star). The earthquake hit Barrow Strait on January 8, 2017 at 23:47:12 (UTC), at 74.320°N - 92.305°W and at a depth of 18.9 km.

Another earthquake hit Barrow Strait on January 9, 2017, this time with a magnitude of 5.2 on the Richter scale, within a day of the earlier M5.8 quake (both in orange on map below). These two earthquakes are among the largest quakes to hit the area in the past five years (map area shows all M1+ quakes since January 9, 2012).

These earthquakes are important, given their magnitude and given that they hit an area without large faultlines (though earthquakes are not uncommon here, also see this discussion). Importantly, these earthquakes occurred in an area prone to glacial isostatic adjustment, as illustrated by the image below.

From "http://grace.jpl.nasa.gov", (unfiltered version). Credit: A, G., J. Wahr, and S. Zhong (2013) "Computations
of the viscoelastic response of a 3-D compressible Earth to surface loading: an application to Glacial Isostatic
Adjustment in Antarctica and Canada", Geophys. J. Int., 192, 557–572, doi: 10.1093/gji/ggs030

Glacial isostatic adjustment as a phenomenon typically takes place over relatively long periods. Yet, extreme weather events can trigger earthquakes in areas that are already on the edge.

The extreme weather situation is depicted by the combination image below.

Similar to the M4.6 earthquake that hit Baffin Island on February 12, 2015, this earthquake occurred at a time when surface temperature anomalies over parts of North America and Greenland were at the bottom end of the scale. At the same time, temperature anomalies over the Arctic Ocean are at the top end of the scale, as illustrated by the left panel in above image. The right panel in above image shows pressure differences reaching the top and bottom ends of the scale.

Earthquakes in the Arctic Ocean are dangerous as they can destabilize methane hydrates. Huge amounts of methane are present in sediments under the Arctic Ocean in the form of free gas and hydrates. Earthquakes can send out strong tremors through the sediment and shockwaves through the water, which can trigger further earthquakes, landslides and destabilization of methane hydrates. The situation is especially dangerous when combined with extreme weather events that can cause cracks and movement in sediments.

Above map, from an earlier post, shows the location of fault lines on the Northern Hemisphere.

The combination image below shows methane levels on January 9, 2017, am, at two different altitudes.

[ click on images to enlarge ]

As temperatures in the Arctic Ocean keep rising, the jet streams and polar vortex are changing their shapes. The North Polar Jet Stream becomes more wavy, and this makes that more extreme weather events can happen such as the events described above.

The situation is dire and calls for comprehensive and effective action, as described at the Climate Plan.


Links

• Climate Plan
http://arctic-news.blogspot.com/p/climateplan.html

• Seafloor Methane
http://arctic-news.blogspot.com/2016/12/seafloor-methane.html

• High Methane Levels Follow Earthquake in Arctic Ocean
http://arctic-news.blogspot.com/2016/07/high-methane-levels-follow-earthquake-in-arctic-ocean.html

• Something had to give - Baffin Island hit by M4.6 earthquake
http://arctic-news.blogspot.com/2015/02/something-had-to-give-baffin-island-hit-by-m4.6-earthquake.html

• Ring Of Ice
http://arctic-news.blogspot.com/2014/08/ring-of-ice.html

• High Methane Levels over Laptev Sea
http://arctic-news.blogspot.com/2013/10/high-methane-levels-over-laptev-sea.html

• Methane Release caused by Earthquakes
http://arctic-news.blogspot.com/2013/09/methane-release-caused-by-earthquakes.html

• Sea of Okhotsk
http://methane-hydrates.blogspot.com/2013/06/sea-of-okhotsk.html

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High Methane Levels Follow Earthquake in Arctic Ocean

In the 12 months up to July 14, 2016, 48 earthquakes with a magnitude of 4 or higher on the Richter scale hit the map area of the image below, mostly at a depth of 10 km (6.214 miles).

As temperatures keep rising and as melting of glaciers keeps taking away weight from the surface of Greenland, isostatic rebound can increasingly trigger earthquakes around Greenland, and in particular on the faultline that crosses the Arctic Ocean.

Two earthquakes recently hit the Arctic Ocean. One earthquake hit with a magnitude of 4.5 on the Richter scale on July 9, 2016. The other earthquake hit with a magnitude of 4.7 on the Richter scale on July 12, 2016, at 00:15:24 UTC, with the epicenter at 81.626°N 2.315°W and at a depth of 10.0 km (6.214 miles), as illustrated by the image below.

Following that most recent earthquake, high levels of methane showed up in the atmosphere on July 15, 2016, over that very area where the earthquake hit, as illustrated by the image below.

Above image shows that methane levels were as high as 2505 ppb at an altitude of 4,116 m or 13,504 ft on the morning of July 15, 2016. At a higher altitude (of 6,041 m or 19,820 ft), methane levels as high as 2598 ppb were recorded that morning and the magenta-colored area east of the north-east point of Greenland (inset) looks much the same on the images in between those altitudes. All this indicates that the earthquake did cause destabilization of methane hydrates contained in sediments in that area.

Above image, from another satellite, confirms strong methane releases east of Greenland on the afternoon of July 14, 2016, while the image below shows high methane levels on July 16, 2016, along the faultline that crosses the Arctic Ocean.

The image on the right shows glaciers on Greenland and sea ice near Greenland and Svalbard on July 15, 2016. Note that clouds partly obscure the extent of the sea ice decline.

Above image shows the sea ice on July 12, 2016. There is a large area with very little sea ice close to the North Pole (left) and there is little or no sea ice around Franz Josef Land (right). Overall, sea ice looks slushy and fractured into tiny thin pieces. All this is an indication how warm the water is underneath the sea ice.

[ click on image to enlarge ]

In addition to the shocks and pressure changes caused by earthquakes, methane hydrate destabilization can be triggered by ocean heat reaching the seafloor of the Arctic Ocean. Once methane reaches the atmosphere, it can very rapidly raise local temperatures, further aggravating the situation.

Temperatures are already very high across the Arctic, as illustrated by the image below, showing that on July 16, 2016, it was 1.6°C or 34.8°F over the North Pole (top green circle), while it was 32.7°C or 90.8°F at a location close to where the Mackenzie River flows into the Arctic Ocean (bottom green circle).

Arctic sea ice is in a very bad shape, as also illustrated by the Naval Research Laboratory nowcast below.

Sea ice thickness has fallen dramatically over the years, especially the ice that was more than 2.5 m thick. The image below compares the Arctic sea ice thickness (in m) on July 15, for the years from 2012 (left panel) to 2015 (right panel), using Naval Research Laboratory images.

[ Click on image to enlarge ]

The image below shows sea surface temperature anomalies from 1961-1990 on July 24, 2016.

Sea surface temperatures off the coast of America are high and much of this ocean heat will be carried by the Gulf Stream toward the Arctic Ocean over the next few months.

On July 24, 2016, sea surface temperature near Florida was as high as 33.2°C or 91.7°F, an anomaly of 3.7°C or 6.6°F from 1981-2011 (bottom green circle), while sea surface temperature near Svalbard was as high as 17.3°C or 63.2°F, an anomaly of 12.6°C or 22.8°F from 1981-2011 (top green circle).

A cold freshwater (i.e. low salinity) lid sits on top of the ocean and this lid is fed by precipitation (rain, hail, snow, etc.), melting sea ice (and icebergs) and water running off the land (from rivers and melting glaciers on land). This lid reduces heat transfer from ocean to atmosphere, and thus contributes to a warmer North Atlantic where huge amounts of heat are now carried underneath this lid toward the Arctic Ocean. The danger is that more ocean heat arriving in the Arctic Ocean will destabilize clathrates at the seafloor and result in huge methane eruptions, as discussed in earlier posts such as this one.

As temperatures keep rising, snow and ice in the Arctic will decline. This could result in some 1.6°C or 2.88°F of warming due to albedo changes (i.e. due to decline both of Arctic sea ice and of snow and ice cover on land). Additionally, some 1.1°C or 2°F of warming could result from methane releases from clathrates at the seafloor of the world's oceans. As discussed in an earlier post, this could eventuate as part of a rise from pre-industrial levels of as much as 10°C or 18°F, by the year 2026.

[ click on image to enlarge ]

The impact of rising temperatures will be felt firstly and most strongly in the Arctic, where global warming is accelerating due to numerous feedbacks that can act as self-reinforcing cycles.

Already now, this is sparking wildfires across the Arctic.

Above image shows wildfires (indicated by the red dots) in Alaska and north Canada, on July 15, 2016.

The image on the right shows smoke arising from wildfires on Siberia. The image below shows that, on July 18, 2016, levels of carbon monoxide (CO) over Siberia were as high as 32318 ppb, and in an area with carbon dioxide (CO2) levels as low as 345 ppm, CO2 reached levels as high as 650 ppm on that day.

[ click on images to enlarge them ]

The image below shows the extent of smoke from wildfires in Siberia on July 23, 2016.

The image below shows high methane levels over Siberia on July 19, 2016.

The image below, from the MetOp satellite, shows high methane levels over Siberia on July 21, 2016.

Below are further images depicting mean global methane levels, from 1980-2016 (left) and 2012-2016 (right).

The image below shows methane levels at Barrow, Alaska.

The image below shows that, while methane levels may appear to have remained stable over the past year when taking measurements at ground level, at higher altitudes they have risen strongly.

The conversion table below shows the altitude equivalents in feet, m and mb.

57016 feet	44690 feet	36850 feet	30570 feet	25544 feet	19820 feet	14385 feet	8368 feet	1916 feet
17378 m	13621 m	11232 m	9318 m	7786 m	6041 m	4384 m	2551 m	584 m
74 mb	147 mb	218 mb	293 mb	367 mb	469 mb	586 mb	742 mb	945 mb

The situation is dire and calls for comprehensive and effective action, as described at the Climate Plan.

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