Showing posts with label fault line. Show all posts
Showing posts with label fault line. Show all posts

Tuesday, November 5, 2013

Methane, Faults and Sea Ice

Shield breaking down

Until now, Arctic sea ice has been acting as a shield, in a number of ways, including:
  • preventing sunlight from warming up water underneath the sea ice 
  • facilitating currents that currently cool the bottom of the sea
  • preventing much methane from entering the atmosphere; as discussed in an earlier post, the sea ice collects and holds the methane in places close enough to the surface for the methane to be consumed through photochemical and biochemical oxidation. 
However, as the sea ice declines, this shield is breaking down. As a result:
  • more sunlight is reaching the water, contributing to warming of water in the Arctic Ocean
  • sea ice decline comes with the danger of weakened currents that cool the seabed
  • more methane is able to penetrate the cracks and openings in the ever-thinner ice. 
Warm Water traveling along Gulf Stream

At the same time, global warming is causing more extreme weather events to occur, such as the record warmth observed in July 2013 in part of the northeastern Atlantic Ocean off the coast of North America. As discussed in a recent post, this warm water has meanwhile traveled along the Gulf Stream and reached the Arctic Ocean.

Methane venting from Seabed

As a result, warmer water is now destabilizing sediments under the seabed that hold huge amounts of methane in the form of free gas and hydrates. Methane is now venting from the seabed of the Arctic Ocean, driven by sea ice decline and "by Gulf Stream heating, earthquakes and deep pyroclastic eruptions", as Malcolm Light explains in a recent comment and as described in an earlier post.

The image below shows the result: Massive amounts of methane venting from the seabed, penetrating the sea ice, and entering the atmosphere over the Arctic Ocean. 


Methane, Faults and Sea Ice

The animation below illustrates links between: 
  • The fault line that crosses the Arctic Ocean and forms the boundery between two tectonic plates (i.e. the North American Plate and the Eurasian Plate)
  • Arctic sea ice, which until now has acted as a shield
  • The prominence of high methane readings over the Arctic Ocean 

Monday, October 28, 2013

Methane over Arctic Ocean is increasing


[ click on image to enlarge ]

Above image shows the Northern Hemisphere on October 26 - 27, 2013, a period of just over one day. Methane readings of 1950 ppb and higher show up in yellow. Peak reading on October 27, 2013, was 2369 ppb.

The image below, created by Harold Hensel with methanetracker, shows methane over the Arctic Ocean in three ranges, with the highest readings (1950 ppb and higher) in red.

[ click on image to enlarge ]
Harold adds: "Methane increased again in the Arctic Circle yesterday, 10/27/2013. So what were the headlines in the news? It wasn't this which is more important than anything the media has to report. This is surreal to me." - at Facebook

Related

- The Unfolding Methane Catastrophe
http://arctic-news.blogspot.com/2013/10/unfolding-methane-catastrophe.html

- Methane hydrates
http://methane-hydrates.blogspot.com/2013/04/methane-hydrates.html

- Myths about methane hydrates
http://methane-hydrates.blogspot.com/p/myths.html

- High Methane Readings continue over Depth of Arctic Ocean
http://arctic-news.blogspot.com/2013/10/high-methane-readings-continue-over-depth-of-arctic-ocean.html

- Abrupt Climate Change
http://arctic-news.blogspot.com/2013/10/abrupt-climate-change.html

- Just do NOT tell them the monster exists
http://arctic-news.blogspot.com/2013/10/just-do-not-tell-them-the-monster-exists.html



Saturday, October 26, 2013

Earthquake hits waters off Japan

An earthquake with a magnitude of 7.3 on the Richter scale hit the waters 231 miles (371 kilometers) east of Japan on October 25, 2013, reports rt.com, adding that the quake prompted an evacuation at the devastated Fukushima Daiichi plant and that strong tremors could be felt on Japan’s main Honshu Island, as well as on the northern island of Hokkaido.

USGS.gov reported the quake as having a magnitude of 7.1 followed up by several smaller quakes, as indicated on the image below, which also indicates the location of Fukushima.

[ click to enlarge ]

The image below shows that methane readings of 1950+ were recorded on and around the location where the earthquake hit. The image merely shows methane that did enter the atmosphere. More methane will have escaped from the seabed, but much of it will have oxidized in the water.


The occurence of this earthquake is very worrying, due to the situation at the Fukushima Daiichi nuclear plant. It is also relevant to the situation in the Laptev Sea, north of Siberia, for a number of reasons, including: 
  1. As the above image clearly shows, earthquakes can trigger methane releases from the seabed, as previously discussed in the post Methane Release caused by Earthquakes.
  2. Global warming is contributing to the occurance of earthquakes. For years, geophysical hazard specialist Bill McGuire has studied this impact of global warming, in particular the Earth's crust bouncing and bending in response to the melting of the great ice sheets and the filling of the ocean basins—dramatic geophysical events that triggered earthquakes, spawned tsunamis, and provoked a series of eruptions from the world's volcanoes. Bill McGuire warns that staggering volumes of melt water poured into the ocean basins, warping and bending the crust around their margins. The resulting tossing and turning provoked a huge resurgence in volcanic activity, seismic shocks, and monstrous landslides—the last both above the waves and below.

    According to calculations posted by Doyle Doss in January 2012, the increase in weight of the Pacific Ocean over the last 50 years due to freshly introduced water from land ice melt is 10 Trillion 331 Billion 125 Million 200 Thousand TONS. In conclusion, global warming is making methane releases triggered by seismic activity worse. 
  3. The fault lines around Japan are interconnected with other fault lines, as illustrated by the image below, from the post High Methane Levels over Laptev Sea, showing methane readings on October 20, 2013 pm. Earthquakes can trigger further earthquakes, especially along the same or interconnected fault lines. 


The image below shows methane readings on October 25, 2013 pm, indicating that high methane readings continue to be recorded over the Laptev Sea.

[ click to enlarge ]
The above image also shows that the Laptev Sea was hit by an earthquake with a magnitude of 4.6 on the Richter scale on September 28, 2013. Earlier, on August 7 and on September 9, earthquakes with similar magnitudes had hit the Laptev Sea closer to land, as described in the post Earthquake hits Laptev Sea.

For more than a month, large amounts of methane have been present over the Arctic Ocean, in particular over the Gakkel Ridge and, more recently, also over the Laptev Rift.

Sediments under the Arctic Ocean contain huge amounts of methane in the form of hydrates and free gas. Some areas, such as the Gakkel Ridge and the Laptev Rift are prone to earthquakes, volcanoes and landslides, as they are part of a tectonic fault line that crosses the Arctic Ocean.

The danger is that, as the permafrost retreats and the snow and ice cover declines rapidly, methane in the Arctic is on the brink of being released abruptly and in large quantities from the seabed. A single earthquake, perhaps even outside of the Arctic Ocean could set this off. There are many more factors that influence seismic activity, such as the position of sun, moon and stars, and the depth at which seismic activity occurs, as tremors can be felt far away from earthquakes that occur at greater depth. Anyway, the danger is that earthquakes will trigger abrupt release of methane from the seabed of the Arctic Ocean, and since methane is a powerful greenhouse gas, such a release could further accelerate local warming, triggering further destabilization of methane in the seabed, escalating into abrupt climate change across the globe.

The depth of the seabed is also important in this regard, since shallow seas can warm up rapidly, while methane that escapes from the seabed has less chance to get oxidized in shallow seas. Large parts of the Arctic Ocean are very shallow, in particular the Laptev Sea, as further descibed in the post methane hydrates.



Saturday, September 21, 2013

High Methane Readings over Arctic Ocean

The image below shows a lot of methane over the Arctic Ocean on September 19, 2013 (pm).


Very worrying are the high methane readings close to Gakkel Ridge, the divergent fault line at the center of the Arctic Ocean, as earlier discussed in the post Methane Release caused by Earthquakes.

Furthermore very worrying are the high methane readings in between Greenland and Novaya Zemlya that coincide with high sea surface temperatures in that area. As discussed in the earlier post Is the North Pole no ice-free?, there are hot spots in the Arctic Ocean where sea surface temperatures are well over 10°C (50°F), which could be caused by undersea volcanic activity; this is the more dangerous as the area has seen methane bubbling up from destabilized hydrates.

For reference, images are added below of sea surface temperatures (top) and sea surface temperature anomalies (underneath) for September 19, 2013, showing sea surface temperatures recorded close to Svalbard that are far higher than even in the waters closer to the Atlantic Ocean.


Also for reference, highest mean and peak methane readings up to September 19, 2013, are added below.



Friday, August 31, 2012

Two earthquakes off the coast of Jan Mayen Island

Two earthquakes struck the waters off the coast of Jan Mayen Island on August 30, 2012. One had  a magnitude of 6.8 on the Richter Scale and occurred at 13:43 pm (UTC), and was followed eight minutes later by a second one with a magnitude of 5.2 on the Richter Scale that took place on 13:51 pm (UTC).

The location of the earthquakes is indicated by the blue square on the top left of the USGS map below.


The Google map below shows that the location is on fault line extending north into the Arctic Ocean.



The map below shows the two earthquakes at the top in orange. The map shows all earthquakes with a magnitude 5.0 or higher that happened worldwide from August 1 to 30, 2012.


The largest earthquake in August 2012 was a magnitude 7.7 quake on August 14 in the Sea of Okhotsk, close to Sakhalin, Russia's largest island.  With a depth of 626 km (389 miles), it was a "deep-focus" earthquake. Such quakes can be felt at great distance from their epicenters.

As the above map shows, this 7.7 M earthquake and the two recent ones off the coast of Jan Mayen Island occurred on the same fault line that goes over the Arctic. The danger is that further earthquakes on this fault line could destabilize methane hydrates in the Arctic, triggering release of huge amounts of methane.

The map below, from this page, shows fault lines and elevation in meters.



In 2011, a number of posts were added on this topic at knol, which has meanwhile discontinued. These posts have been preserved at the following pages:
Methane linked to Seismic Activity in the Arctic
Runaway warming
Thermal expansion of the Earth's crust necessitates geoengineering