M4.5 Earthquake hits Arctic Ocean

An earthquake with a magnitude of 4.5 on the Richter scale hit the Arctic Ocean on April 13, 2014, at 02:12:19 UTC at a depth of 10.00 km (6.21 mi).

The epicenter of the quake is located right on the faultline that crosses the Arctic Ocean, at 86.687°N 45.393°E, some 800 km north of Franz Josef Land.

Earthquakes at this location are very worrying, as they can destabilize hydrates contained in the sediment under the seafloor of the Arctic Ocean. Furthermore, one earthquake can trigger further earthquakes, especially at locations closeby on the same faultline.

Has the descent begun?

On March 9, 2014, Arctic sea ice area was at a record low for the time of the year, at only 12.88731 square kilometers.

Sea ice extent shows a similar descent, as illustrated by the NSIDC image below.

NSIDC update: The image below shows that Arctic sea ice extent was 14.583 square kilometers on March 11, 2014 (light green line), a record low for this time of the year and smaller than it was in 2006 (magenta line) and 2011 (orange line) at this time of the year.

The situation is dire, given that methane concentrations have risen strongly following an earthquake that hit the Gakkel Ridge on March 6, 2014, as illustrated by the image below.

[ click on image to enlarge ]

Huge amounts of methane have been released from the seafloor of the Arctic Ocean over the past half year, and the resulting high methane concentrations over the Arctic will contribute to local temperature rises.

The image below shows that sea surface temperatures are anomalously high in the Arctic Ocean and off the east coast of North America, from where warm water is carried by the Gulf Stream into the Arctic Ocean.

The prospect of an El Niño event makes the situation even more dire. NOAA recently issued an El Niño Watch. This follows a conclusion by an international research team that found a 75% likelyhood of an El Niño event in late 2014.

The consequences of sea ice collapse would be devastating, as all the heat that previously went into transforming ice into water will be asbsorbed by even darker water, from where less sunlight will be reflected back into space. The danger is that further warming of the Arctic Ocean will trigger massive methane releases is unacceptable and calls for comprehensive and effective action as discussed at the Climate Plan blog.

M4.5 Earthquake hits Gakkel Ridge

The above image shows recent large methane release over the Gakkel Ridge, the faultline that crosses the Arctic Ocean between the northern tip of Greenland and the Laptev Sea (red line on map). Methane readings were as high as 2395 ppb at 586 mb, an altitude that often shows high methane readings originating from the Arctic Ocean.

An earthquake with a magnitude of 4.5 hit the Gakkel Ridge at a depth of 2 km on March 6, 2014, at 11:17.17.0 UTC. The location is shown on the map below.

[ click on image to enlarge ]

The image below shows more recent methane readings, around March 8, 2014.

The image below is a Naval Research Laboratory forecast of sea ice thickness for March 8, 2014, run on March 3, 2014.

Meanwhile, the sea ice is close to record lows (for the time of the year), as illustrated by the images below. The image directly below shows sea ice area.

The image below shows sea ice extent.

The image below, by Wipneus, shows sea ice volume.

The image below, by Andy Lee Robinson, offers a different way of looking at sea ice volume, the Arctic Death Spiral.

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 

Causes of high methane levels over Arctic Ocean

Methane levels in the atmosphere over the Arctic Ocean are very high, as illustrated by the image below, by Leonid Yurganov, showing IASI methane readings for October 11-20, 2013.

Previous posts have discussed these high levels of methane, pointing at links between high methane levels over Arctic Ocean and earthquakes and volcanic activity.

Malcolm Light points at another factor that is contributing to the high methane levels observed over the Arctic Ocean in October 2013.

Malcolm says: The massive methane release in the Arctic this October is partly because the Gulf Stream waters got massive heating in the Atlantic off the North American coast in July. It takes the Gulf Stream currents almost 4 months to reach the emission sites along the southern side and end of the Eurasian Basin. This combined with the earthquake activity along the Gakkel Ridge and deep pyroclastic eruptions is escalating the rate of methane release by destabilizing the submarine Arctic methane hydrates at increasing rates.

The NOAA image below shows temperature anomalies for July 2013. NOAA adds that in July 2013 many regions were much warmer than average, with part of the northeastern Atlantic off the coast of North America observing record warmth.

The image below shows how water traveling along the Gulf Stream ends up in the Arctic Ocean. Water in the Gulf Stream travels at 4 miles per hour, but slows down to less than 1 mile per hour in the North-Atlantic Current. This means that water warmed up off Florida in July will start reaching waters beyond Svalbard in October.

The image below, from Malcolm Light's September 2012 post Further Confirmation of a Probable Arctic Sea Ice Loss by Late 2015, shows how warm water flows into the Arctic Ocean and warms up methane hydrates and free gas held in sediments under the Arctic Ocean.

 The image below shows the methane readings over the past few days on the Northern Hemisphere.

High Methane Levels over Laptev Sea

A major fault line crosses the Arctic Ocean, forming the boundery between two tectonic plates, the North American Plate and the Eurasian Plate. These plates slowly diverge, creating seismic tension along the fault line.

From where the Mid-Atlantic ridge enters the Arctic Ocean, it is called the Gakkel Ridge. The fault continues as the Laptev Sea Rift, on to a transitional deformation zone in the Chersky Range in Siberia, then the Ulakhan Fault between the North American Plate and the Okhotsk Plate, and then continues as the Aleutian Trench to the end of the Queen Charlotte Fault system.

Above map shows the location of some of the main points of interest, i.e. the Laptev Sea Rift and the Gakkel Ridge, where high methane readings have been recorded recently, as shown in the image below. Indicated in yellow are all methane readings of 1950 ppb and over, for a period of just over one day, October 19 - 20, 2013.  

To pointpoint more closely where methane is venting along the Laptev Sea Rift, the image below gives readings for October 20, 2013, pm, at just three altitudes (607 - 650 mb). 

This is a very dangerous situation, since high levels of methane have been recorded over the Arctic Ocean for more than a month now. Furthermore, large amounts of methane have vented in the Laptev Sea area in previous years. Added below is an edited part of a previous post, Unfolding Climate Catastrophe. 

In September 2005, extremely high concentrations of methane (over 8000 ppb, see image on the right) were measured in the atmospheric layer above the sea surface of the East Siberian Shelf, along with anomalously high concentrations of dissolved methane in the water column (up to 560 nM, or 12000% of super saturation).

The authors conclude: "Since the area of geological disjunctives (fault zones, tectonically and seismically active areas) within the Siberian Arctic shelf composes not less than 1-2% of the total area and area of open taliks (area of melt through permafrost), acting as a pathway for methane escape within the Siberian Arctic shelf reaches up to 5-10% of the total area, we consider release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time".

In 2007, concentrations of dissolved methane in the water column reached a level of over 5141 nM at a location in the Laptev Sea. For more background, see the previous post, Unfolding Climate Catastrophe. 

Satellite measurements show methane readings of up to 2411 ppb on October 20, 2013. Sadly, no current data are available from measurements in the Laptev Sea, neither methane levels in the water, nor atmospheric methane levels just above sea level. Perhaps in time, some data will become available from expeditions.

Unfolding Methane Catastrophe

The above image shows that, over a period of less than two days, huge amounts of methane show up over the depth of the Arctic Ocean, especially along the fault line that crosses the Arctic Ocean and extends into Siberia and further into the Sea of Okhotsk. On October 17, 2013, readings of up to 2351 ppb were recorded.

The above image shows that such high readings have occurred before over the past few months. This time, however, this high reading can be more clearly attributed to methane escaping from the depth of the Arctic Ocean, as also indicated by the image below that shows that at 469 mb (i.e. the altitude at which this high reading was recorded on the afternoon of October 17) methane was predominantly present at higher northern latitudes.

The methane that appears over the depth of the Arctic Ocean is likely have traveled a long path through the vertical water column before entering the atmosphere. Clearly, some of the methane must have oxidized in the ocean. Therefore, methane must be escaping from the seabed in amounts far higher than what is visible in the air.

Below follows some history regarding this unfolding methane catastrophe. Note that methane concentrations in the water are measured in nM, while methane concentrations in the atmosphere are typically measured in parts per billion (ppb).

There are vast amounts of methane in sediments underneath the Arctic Ocean.  Natalia Shakhova et al. (2010) estimate the accumulated potential for the East Siberian Arctic Shelf (ESAS) region alone (image on the right) as follows:

• organic carbon in permafrost of about 500 Gt
• about 1000 Gt in hydrate deposits
• about 700 Gt in free gas beneath the gas hydrate stability zone.⁸

Natalia Shakhova et al. (2008) consider release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time. By comparison, the total amount of methane currently in the atmosphere is about 5 Gt.³

The danger that volcanic and earthquake activity along the Gakkel Ridge could lead to destabilization and abrupt methane release into the atmosphere was highlighted by Light and Sorana back in 2002.¹

Measurements taken in September 2003 and September 2004 show that the surface layer of shelf water in the East-Siberian Sea and Laptev Sea was supersaturated up to 2500% relative to the present average atmospheric methane content of 1.85 ppm. Anomalously high concentrations (up to 154 nM or 4400% supersaturation) of dissolved methane in the bottom layer of shelf water suggest that the bottom layer is somehow affected by near-bottom sources. Considering the possible formation mechanisms of such plumes, we favor thermo-abrasion and the effects of shallow gas or gas hydrates release, conclude the authors of this study, published in 2005.²

In September 2005, extremely high concentrations of methane (up to 8 ppm) were measured in the atmospheric layer above the sea surface of the East Siberian Shelf, along with anomalously high concentrations of dissolved methane in the water column (up to 560 nM, or 12000% of super saturation).³

The authors conclude: "Since the area of geological disjunctives (fault zones, tectonically and seismically active areas) within the Siberian Arctic shelf composes not less than 1-2% of the total area and area of open taliks (area of melt through permafrost), acting as a pathway for methane escape within the Siberian Arctic shelf reaches up to 5-10% of the total area, we consider release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time. That may cause ∼12-times increase of modern atmospheric methane burden with consequent catastrophic greenhouse warming".³

In 2007, concentrations of dissolved methane in the water column reached a level of over 5141 nM at a location in the Laptev Sea.⁴

A study published in 2008 found volcanoes up to 2,000 m in diameter and a few hundred metres high at the bottom of the Arctic Ocean, at Gakkel Ridge.⁵

End September 2011, a cluster of methane plumes, over one km in diameter, appeared in the Laptev Sea, as shown on the image below, from a paper on the unfolding "Methane Catastrophe".⁶

In early October 2013, high atmospheric levels of methane started to appear over the depth of the Arctic Ocean.⁹  See image at top for most recent readings.


References

1. Arctic Methane Hydrates: A Potential Greenhouse Gas Hazard. - Light, M.P.R. and Solana, C. (2002)
http://adsabs.harvard.edu/abs/2002EGSGA..27.4077L
For more details, see also
http://arctic-news.blogspot.com/p/seismic-activity.html

2. The distribution of methane on the Siberian Arctic shelves: Implications for the marine methane cycle. - Natalia Shakhova, Igor Semiletov and Gleb Panteleev (2005)
http://onlinelibrary.wiley.com/doi/10.1029/2005GL022751/abstract

3. Anomalies of methane in the atmosphere over the East Siberian shelf: Is there any sign of methane leakage from shallow shelf hydrates? - N. Shakhova, I. Semiletov, A. Salyuk and D. Kosmach (2008)
http://meetings.copernicus.org/www.cosis.net/abstracts/EGU2008/01526/EGU2008-A-01526.pdf

4. Siberian Sea Shelf Study, International Arctic Research Center, University of Alaska Fairbanks
http://research.iarc.uaf.edu/SSSS/data2010.php

5. Explosive volcanism on the ultraslow-spreading Gakkel ridge, Arctic Ocean. - Sohn RA et al. (2008)
http://www.ncbi.nlm.nih.gov/pubmed/18580949

6. The Degradation of Submarine Permafrost and the Destruction of Hydrates on the Shelf of East Arctic Seas as a Potential Cause of the “Methane Catastrophe”: Some Results of Integrated Studies in 2011. - V. I. Sergienko et al., in Oceanology (Sept. 2012)
http://link.springer.com/article/10.1134/S102833

7. On carbon transport and fate in the East Siberian Arctic land–shelf–atmosphere system. - Semiletov et al. (2012)
http://iopscience.iop.org/1748-9326/7/1/015201

8. Methane release from the East Siberian Arctic Shelf and the Potential for Abrupt Climate Change. - Natalia Shakhova and Igor Semiletov (2010), Presentation at Symposium, November 30, 2010
http://symposium2010.serdp-estcp.org/content/download/8914/107496/version/3/file/1A_Shakhova_Final.pdf

9. 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

Post by Sam Carana.

Earthquake hits Laptev Sea

An earthquake with a magnitude of 4.6 on the Richter scale hit the Laptev Sea on September 28, 2013.

[ click on image to enlarge ]

This follows a number of earthquakes on or close to the fault line that crosses the Arctic Ocean and extends into Siberia, as shown on above map and on the map below.

[ click to enlarge ]

Furthermore, as earlier discussed in the post Methane release caused by earthquakes, there has been a lot of seismic activity in the Aleutian Islands region all the way up into Alaska, including an earthquake with a magnitude of 7 on the Richter scale on August 30, 2013, and several more recent earthquakes with a higher magnitude than 6 on the Richter scale.

This is a lot of seismic activity for the Arctic, given that this is a relatively quiet part of the globe in terms of earthquakes.

[ click on image to enlarge ]

As above map shows, there were 1250 earthquakes with a magnitude of 2.5 or higher over the past 30 days globally. About 90% of the world's earthquakes occur along the Ring of Fire, on the edges of the Pacific Ocean.

The fault line that crosses the Arctic Ocean marks the boundery between the North American Plate and the Eurasian Plate. Along this fault, huge amounts of methane are held in sediments, in the form of free gas and hydrates. The danger is that earthquakes along this fault will destabilize methane, causing it to rise abruptly in large amounts and enter the atmosphere.

As the top image shows, a lot of methane is currently present in the atmosphere along this fault line. Methane has shown up there repeatedly, indicating that methane there has been prone to release for some time and warning that even larger releases could occur soon.

Related posts

- Methane release caused by earthquakes (2013)
http://arctic-news.blogspot.com/2013/09/methane-release-caused-by-earthquakes.html

- North Hole (2013)

http://arctic-news.blogspot.com/2013/09/north-hole.html

- Sea of Okhotsk (2013)
Methane-hydrates.blogspot.com/2013/06/sea-of-okhotsk.html

- Seismic activity, by Malcolm Light and Sam Carana (2011)
Arctic-news.blogspot.com/p/seismic-activity.html

- Thermal expansion of the Earth's crust necessitates geoengineering (2011)
Arctic-news.blogspot.com/p/thermal-expansion.html

Post by Sam Carana.

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.