West Coast of Chile (two above) http://go.nasa.gov/2iPu2cg
The effects of earthquakes in the Arctic on methane hydrates
Background from Sam Carana on the effect of quakes on methane hydrates.
Methane Release caused by Earthquakes
Arctic News, 15 September, 2013
Methane hydrates can become destabilized due to changes in temperature or pressure, as a result of earthquakes and shockwaves accompanying them, severe storms, volcanic activity, coastal collapse and landslides. As an example, an earthquake followed by methane release was discussed in the post Sea of Okhotsk a few months back. Such events can be both primed and triggered by global warming, particularly in the Arctic, as follows:
As more ice melts away on Greenland and more water runs off into the sea, there is less weight on the Earth’s crust under Greenland. The crust and mantle can bounce back during a large melt, an effect that is called ‘isostatic rebound’. This rebound can not only trigger earthquakes and landslides, it can also suck up the magma in the Earth’s crust to the surface and trigger volcanic eruptions.
The added weight of water from melting glaciers stresses the Earth’s crust underneath the sea, which can cause earthquakes. This is especially the case for coastal waters, where the impact of the water that flows into the sea is huge, not only in terms of weight, but also in terms of the currents they cause. As the permafrost melts, mountain ranges, soil and submarine sediments all become less robust. Where the permafrost previously held things together, we can now expect more coastal collapse, avalanches and landslides, which can send shockwaves through the sea that in turn trigger earthquakes and hydrate destabilization.
Methane hydrates that are on the edge of stabilization can be disturbed by global warming in two additional ways, temperature and pressure: Warming of the Earth’s crust as heat penetrates sediments on the seafloor. Thermal expansion of the Earth’s crust means that the crust will expand slightly in volume, resulting in expansion of the cavity that holds the hydrates.
Finally, there’s the additional impact of methane itself. Permafrost previously kept methane stable in sediments. Methane converting from hydrates into free gas will expand some 160 times in volume; this explosive process can trigger further destabilization. Once released into the atmosphere, the methane has a huge local warming potential, adding to the threat that further methane releases will occur locally.
SECOND EARTHQUAKE NEAR NORTH POLE IN 18 HOURS
Seemorerocks: Superstation95, 9 January, 2017
A SECOND earthquake has taken place within 24 hours, in the Barrow Strait waterway, north of the Arctic Circle. Today’s quake measured Magnitude 5.2 and was at a shallow depth of about 15 km. This comes only eighteen hours after an earlier, larger, deeper quake, measuring Magnitude 5.8 in almost the identical location! The two quakes have taken place in an area where there are no known active seismic faults. In addition, the area in which these quakes has taken place is made up of such old, hard rock, the vibrations from both quakes traveled extraordinary distances, being detected on Seismographs at the Yellowstone National Park super-volcano, 2144 miles to the southwest, and also being recorded on the US Geological Survey ANSS Backbone, as far away as New Mexico!
Here is one of the seismograms from Yellowstone showing both quakes, the larger at the top, and today’s at the bottom – both in red: [link]… It is very unusual for earthquakes of this size to strike in this location, and extraordinary that two such quakes have struck in the same area within 18 hours. Scientists cannot offer an explanation for these developments.
Crying ghost in upper-right ….
The Gulf of Mexico (four above) http://go.nasa.gov/2iPuqan
Florida & Atlantic Ocean (two above) http://go.nasa.gov/2k2enDm
Lake Erie & Ohio (two above) http://go.nasa.gov/2k2dpqp