Sentences with phrase «of subducting»

We used local observations recorded within 100 to 150 miles to map the structures at the top of the subducting plate.»

Now a team of researchers, led by Teh - Ru Alex Song of the Carnegie Institution's Department of Terrestrial Magnetism, has found that an anomalous layer at the top of a subducting plate coincides with the locations of slow earthquakes and non-volcanic tremors.

In contrast, off the coast of central Oregon, the thick layer of subducting sediments are less compact, with water in the pore space between the grains.

The intermediate - depth regions of the subducting Nazca plate can be segmented into five sections based on their angle of subduction beneath the South America plate.

Earthquakes can also be generated to depths greater than 600 km as a result of continued internal deformation of the subducting Nazca plate.

They looked to compare the density of subducting slabs at that time with the density of the surrounding mantle, the difference of which would determine how far slabs would have sunk.

The Tohoku - oki earthquake occurred along a thin, clay - rich fault zone in the basal strata of the subducting plate.

«Tearing and breakoff of the subducted slabs as the result of a collision of the Panama arc - indenter with northwestern South America,» appears in the June 2013 issue of BSSA.

Water migrates upwards and causes the top of the subducted oceanic crust to melt, producing magma beneath the Cascade volcanoes.

Not exact matches

Off the east coast of New Zealand, the Pacific plate is subducting under the Australian plate.

SASMEX's main focus is on earthquakes originating in the subduction zone off the southern coast of Mexico, where the Cocos tectonic plate subducts below the North American Plate.

Earthquakes are common where a subducting plate grinds against the underside of an overriding plate.

Since we know that Earth's atmosphere first carried measurable quantities of oxygen around 2.45 billion years ago, the crust must have formed and been subducted at least this long ago, Cabral reasons (Nature, DOI: 10.1038 / nature12020).

Over long periods of time (think millions of years), the crust is subducted deep into the mantle.

A new study suggests that instead of a plume of hot mantle that extends down to Earth's core, the real culprit is a subducting tectonic plate that began sinking beneath North America hundreds of millions of years ago.

The complex regional tectonic activity includes movement of three plates: the Caribbean plate that is subducting or being forced beneath Colombia in the north; the Panama block or Panama plate that is colliding with Colombia in the central part of the country; and the Nazca plate, which is an oceanic plate that is subducting beneath the southern part of Colombia from the Pacific.

Now seismologists have identified the «Caldas tear,» which is a break in a slab that separates two subducting plates and accounts for curious features, including a «nest» of seismic activity beneath east - central Colombia and high grade mineral deposits on the surface.

It's a block of thick crust that doesn't subduct easily, rather it subducts at a shallow angle,» said Mann.

Here, a slab of the Pacific Ocean floor called the Juan de Fuca plate slides eastward and downward, «subducting» underneath the continental plate of North America.

Once the movement has begun, it is perpetuated due to the weight of the dense subducting plate.

Klein used the composition of each rock sample to calculate the density of a typical subducting slab, for both the modern day and 3 billion years ago.

He then estimated the average temperature of a modern versus an ancient subducting slab, relative to the temperature of the surrounding mantle.

For the most part, today's subducting slabs can only sink so far, to about 670 kilometers below the surface, before the mantle's makeup turns from a honey - like consistency, to that of paste — too dense for most slabs to penetrate further.

Instead, subducting slabs would have sunk straight to the bottom of the mantle, establishing their final resting place just above the Earth's core.

The combination of a hotter mantle and denser rocks likely caused subducting plates to sink all the way to the bottom of the mantle, 2,800 kilometers below the surface, forming a «graveyard» of slabs atop the Earth's core.

It marks the plate boundary between the subducting Nazca plate and the South America plate, where the oceanic crust and lithosphere of the Nazca plate begin their descent into the mantle beneath South America.

Large intermediate - depth earthquakes (those occurring between depths of approximately 70 and 300 km) are relatively limited in size and spatial extent in South America, and occur within the Nazca plate as a result of internal deformation within the subducting plate.

Using GPS, InSAR, gravity, seismic reflection, and geological data, Marcos Moreno and colleagues from GFZ as well as Chile show that the 2016 earthquake occurred at the deep boundary of a persistent asperity on the interface between the subducting Nazca and overriding South American plates, where both plates are coupled and not sliding past each other in spite of the high convergence velocity of 68 mm / year.

The subducted Pacific plate beneath the Sea of Okhotsk (located between the Kamchatka Peninsula and the Russian mainland) is a lot colder than the subducted slab where the 1994 Bolivia earthquake occurred.

The team found that the subducting slab — a portion of the oceanic plate that slides beneath a continental plate — is the dominant driving force behind the deformation of the mantle.

«Eastern Australia was drifting over a subducted plate graveyard, giving it a sinking feeling,» said co-author Dr Kara Matthews, a former PhD candidate at the University now at the University of Oxford.

As the model helps explain, a volcano can form inland if the slab subducts at a shallower angle, and a hole in the shallow slab allows for a special type of magma to form by melting of the crust.

It is proposed that the development of this modelling strategy could enable the estimation of critical failure thresholds for other mapped subduction asperities where subducting and overriding plates are currently locked.

That's because the rising magma that produced the lavas probably mixed with upper mantle rocks, which have been contaminated with isotopically heavy surface water that got dragged down by subducting slabs of tectonic plates.

Because such shifts in olivine change the structure of earth's subducted lithosphere, the new phase transition mechanism could help explain the origins of some deep earthquakes.

On the hot young Earth, the outer layer was too weak and soft for plate tectonics to operate until the upper mantle cooled enough to allow sections of crust to slip under each other, or subduct, at collision zones some 3.2 to 2.5 billion years ago.

As the subducting plate sinks deeper into the earth, it encounters higher and higher temperatures and pressures, which release the significant amount of water trapped in waterrich minerals that exist within the slab.

However, the mantle remained so hot that it softened the subducting oceanic crust too much for it to pull large areas of continental crust down behind it, as it does today.

Java is part of a volcanic island arc, formed when one tectonic plate subducts below another.

How much did they affect the ability of the now cooling crust to actually form plates and start to subduct and make plate tectonics?

The northwest Pacific crust that is subducting in this area is some of the oldest, coldest oceanic crust subducting on Earth.

As a result, mantle plumes entrain a variable combination of relatively young oceanic crust directly from the subducting slab, older oceanic crust that has been stirred with ancient more primitive material and background, depleted mantle.

The model showed that if there were varying amounts of salt in the surface ice shell, it could provide the necessary density differences for a slab to subduct.

The warm Atlantic water was saltier, and therefore heavier and subducted at depth and reached to the bottom, actually heating up beneath a lid of ice and melt water, that prevented the release of heat to the atmosphere.

The giant Sumatran earthquake raised questions about the sea - floor - age hypothesis, because the old subducting crust there should have ruled out a shock of that size, says Okal.

The heat and stress causes some of the material on the subducting plate to become a buoyant mineral called serpentinite that rises and erupts out of mud volcanoes.

As long as rapid continental weathering continued, carbonate was deposited on the oceanic crust and subducted into what Lowe calls «a big storage facility... that kept most of the carbon dioxide out of the atmosphere.»

Some geologists think that subducted slabs of lithosphere have settled there.

The scientists will map the distribution of serpentinite in the subducting plate and overlying mantle, by looking for regions where certain seismicwaves travel more slowly than usual.

«For seismic structure, I am focused on delineating the geometry of the Cocos plate, and on characterizing the mantle transition zone and how the subducted plate interacts with it,» she said.