On the morning of March 12, 2020, peak methane levels were as high as 2902 ppb (parts per billion) at a pressure level of 469 mb (millibar, equivalent to an altitude of some 6 km (almost 20,000 feet).
What did cause this very high peak? The image on the right shows the situation at 695 mb.
High levels of methane, colored in magenta, show up over the oceans at high latitudes north, especially around Greenland and around Svalbard.
The image underneath on the right shows methane even closer to sea level, at 1000 mb. At this altitude, such magenta-colored high levels of methane only show up over an area in between Greenland and Svalbard.
It appears that these high methane levels did originate from this area. What could have triggered this?
The image below shows that an earthquake with a magnitude of 4.6 on the Richter scale hit an area in between Greenland and Svalbard on March 11, 2020, at
21:30:03 (UTC), 2020, at depth of 10 km.
It appears that the earthquake did cause destabilization of sediments at the seafloor of the Arctic Ocean in between Greenland and Svalbard, containing methane in the form of hydrates and free gas, with the destabilization resulting in the eruption of methane that subsequently reached the atmosphere.
As illustrated by the image on the right, there were strong differences in pressure in the atmosphere over Greenland on the one hand and over the Arctic Ocean on the other hand, on March 11, 2020, 21:00 UTC.
The next question is if there was something that triggered the earthquake. The image below shows a forecast for March 22, 2020, of conditions in the stratosphere at 10 hPa.
Above image shows a forecast for March 22, 2020, of temperatures as high as 6.2°C or 43.2°F and as low as -68.8°C or -91.9°F at another location at 10 hPa (Polar Vortex), with wind reaching speeds as high as 369 km/h or 229 mph.
The image on the right shows a huge temperature difference between two locations in the stratosphere on March 23, 2020, resulting in wind reaching speeds as high as 341 km/h or 212 mph.
This indicates a strong updraft, carrying huge amounts of relatively warm air from low altitudes over the Arctic up into the stratosphere.
Following a steep fall, Arctic sea ice extent was at a record low for the time of year on March 28, 2020, as illustrated by the image below.
Since the start of 2020, Arctic sea ice volume has been at a record low for the time of year, as the image on the right shows.
These conditions may have acted as a sink plunger, triggering the earthquake and destabilizing sediments at the seafloor, resulting in the methane eruptions.
More generally, the events reflect a huge and growing overall imbalance in the temperature of the atmosphere, and the added methane releases further contribute to this imbalance.
Meanwhile, sea surface temperatures off the coast of North America on March 21, 2020, were as much as 13.2°C or 23.7°F higher than 1981-2011 (at the green circle on the image on the right).
With sea ice thickness this low, it looks like there will be no buffer left to consume ocean heat that gets carried along the path of the Gulf Stream into the Arctic Ocean, which threatens to further destabilize sediments containing huge amounts of methane, as also discussed in an
earlier post.
On top of this, high temperatures keep showing up over the Arctic Ocean in forecasts, as illustrated by the two forecasts below (for March 21, 2020, and for March 31, 2020).
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| Temperature anomaly forecast for March 21, 2020 |
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| Temperature anomaly forecast for March 31, 2020 |
Discussion
As said above, it appears that this M4.6 earthquake on March 11, 2020, caused destabilization of sediments at the seafloor of the Arctic Ocean in between Greenland and Svalbard.
The image on the right shows that earlier, a M5 earthquake hit an area a bit to the north, i.e. on March 3, 2020.
While not much methane showed up locally following that M5 earthquake, high methane readings were recorded elsewhere over large parts of the Arctic Ocean early March 2020, which could have resulted from destabilization along the fault line that crosses the Arctic Ocean (red line).
The next image on the right shows that earthquakes between Greenland and Svalbard over the past decade did predominantly occur on this fault line.
The high methane readings in between Greenland and Svalbard following the M4.6 earthquake could have occurred for the very reason that this earthquake hit an area outside the fault line, where sediments had until now rarely been shaken.
This could imply there could be huge amounts of methane contained in areas outside the fault line, supporting the above warning that ocean heat that gets carried along the path of the Gulf Stream into the Arctic Ocean threatens to further destabilize sediments containing huge amounts of methane. After all, such destabilization can occur as a result of higher temperatures or changes in pressure, or both.
Update
South Greenland was hit by M4.3 and M4.5 earthquakes on April 17, 2020. North Greenland was earlier hit by a M4.6 earthquake, on March 30, 2020.
Earthquakes that hit the Greenland mainland are rare. Earthquakes typically take place on or close to the faultline (red line) that goes over Iceland and extends north, running in between Greenland and Svalbard, as was the case with the M4.2 east of Greenland on April 2, 2020.
This faultline runs across the seafloor of the Arctic Ocean all the way to Russia. Multiple earthquakes hit this faultline recently, including two M4.3 eartquakes, one east of Severnaya Zemlya on April 12, 2020, and one near Tiksi on March 27, 2020.
