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Thousands of ice shelves from Antarctica Rock & # 39; Quakes & # 39; at night




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The disintegration of Antarctic ice shelves – such as Larsen C, seen here in mid 2017 – could be announced by the emergence and rise of the so-called ice quake, collected by seismometers.NASA Goddard

Of his hidden meteorite collections to the old one geological cemeteries hidden beneath the surface, scientists are breaking a remarkable new ground almost every month in relation to Antarctica, possibly the most alien place on the planet.

Now, a new study led by the University of Chicago revealed another curious curiosity. Not only is the ice maker McMurdo subject to a great deal of seriousness, but these shakes follow a daily cycle: during the day, things are quite silent, but at night the rumors arise. The team suspects that everything depends on the way the shelf ice responds to the changing temperature of the surface.

As sunlight reaches the ice during the southern summer, it has been averted a little. At night, semi-melted ice lagoons are decidedly cooled. This causes the ice helmet on the surface to contract; At the same time, the water ponds beneath this superior rigid sheet expand as they freeze. Finally, the ice expands deforms the frozen lid to such an extent that it fits violently, something that & nbsp; detectable by seismometer. When referring to these events as "ice earthquakes", the team explains that they recorded & nbsp; Hundreds of thousands of them every night while the Sun hides.

Glaciers and climatologists closely observe the complicated behavior of the continent's gigantic ice sheet and its ice shelves through various methods. However, all the small ones help and the seismometers, which collect ice earthquakes, could provide an additional way for scientists to remotely watch ice, as it continues to respond to our increasingly hot world.

Ice shelves do not directly contribute to sea level rise when they break down, but as they keep ice off the coast, their destruction essentially opens the gates.NASA Goddard

The enigmatic earthquakes of the frozen continent began to reach a much closer scientific scrutiny from the end. East Antarctica, for example, was supposed to last for a long time in the absence of earthquakes: it is strange, given that it is suffering from prolonged extension by tectonic forces, which must be activating many faults. As it happens, research launched last summer found that apparent asheism had dropped to bias of data: There were simply not enough seismic stations in Antarctica before 2007, and when they were created, tens of earthquakes were stopped.

Earthquakes are not exactly a new idea, but as before, little was known about their presence and activation mechanisms simply because we did not have the instrumentation in place. The seismometers could once again have our rescue, but this time, they are not gathering tectonic tremors in good faith.

Ice quake, despite the name, are not really earthquakes. They can be releasing seismic waves that can be collected by seismometers, but they are not wrong, there are no tectonic forces at work here, which causes the ice to scrub this scale. In fact, these ice earthquakes are perhaps more related to these earthquakes of ice, or cryoseisms, which were collected in Chicago during the recent embodiment of the polar vortex. When the humid soil freezes, the water inside is expanding and, emerging against the earth around it, it can suddenly crash, creating very localized tremors.

The Antarctic ice earthquakes are a bit different from this; They are still driven meteorologically, but there is no soil involved here, just different layers of ice near or on the surface. However, you may consider & nbsp; ice shakes cryospheric cousins ​​for frost earthquakes.

studies

A mechanism in which mechanical instabilities are introduced is through the night's ice expansion close to the surface when recovering from the comparatively scorching daytime environment. The team argues that by understanding this process, and quantifying how often this is happening, our general understanding of the destruction of the ice shelf will be improved.

The researchers created a series of seismometers on the McMurdo Ice Shelf in Antarctica during a recent summer, from November 2016 to January 2017. Near a boring and prone part of the fusion of the shelf, they detected millions of small ice quake during that time.

The fact that these earthquakes only appeared to occur during a period of 6 to 12 hours at night, and that they did not occur in areas of dry ice, betrayed their origin: the interaction of several layers of ice during a freezing cycle And daytime defrosting was the only sensitive explanation here. A simple computer model, which simulated the daily transfer of heat to the surface ice and surface ice, confirmed the suspicions.

Although the team only looked at McMurdo, they suspect that this thermally-regulated shaking can be present on all ice shelves that melt on the surface. This suggests that seismometers may be very good to follow the gradual annihilation of these shelves, with the emergence and any increase in the frequency of earthquakes that reveal a greater vulnerability to climate change.

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The disintegration of Antarctic ice shelves – such as Larsen C, seen here in mid 2017 – could be announced by the emergence and rise of the so-called ice quake, collected by seismometers.NASA Goddard

From its collections of hidden meteorites to the ancient hidden geological cemeteries beneath the surface, scientists are breaking a remarkable new land every month when it comes to Antarctica, possibly the most remote place on the planet.

Now, a new study led by the University of Chicago revealed another curious curiosity. Not only is the ice maker McMurdo subject to a great deal of seriousness, but these shakes follow a daily cycle: during the day, things are quite silent, but at night the rumors arise. The team suspects that everything depends on the way the shelf ice responds to the changing temperature of the surface.

As sunlight reaches the ice during the southern summer, it has been averted a little. At night, semi-melted ice lagoons are decidedly cooled. This causes the ice helmet on the surface to contract; At the same time, the water ponds beneath this superior rigid sheet expand as they freeze. Finally, the ice expands deforms the frozen lid to such an extent that it fits violently, something that is detectable by the seismometers. When referring to these events as "earthquakes", the team explains that they recorded hundreds of thousands of them every night while the Sun hides.

Glaciers and climatologists closely observe the complicated behavior of the continent's gigantic ice sheet and its ice shelves through various methods. Any small help yet, and the seismometers that are collected in ice earthquakes could provide an additional way for scientists to remotely watch the ice as it continues to respond to our increasingly hot world.

Ice shelves do not directly contribute to sea level rise when they break down, but as they keep ice off the coast, their destruction essentially opens the gates.NASA Goddard

The enigmatic earthquakes of the frozen continent began to reach a much closer scientific scrutiny from the end. East Antarctica, for example, was supposed to last for a long time in the absence of earthquakes: it is strange, given that it is suffering from prolonged extension by tectonic forces, which must be activating many faults. As it turned out, the investigations launched last summer found that apparent aseism fell into data bias: there were simply not enough seismic stations in Antarctica before 2007 and, when they were created, tens of earthquakes were stopped.

Earthquakes are not exactly a new idea, but as before, little was known about their presence and activation mechanisms simply because we did not have the instrumentation in place. The seismometers could once again have our rescue, but this time, they are not gathering tectonic tremors in good faith.

Ice quake, despite the name, are not really earthquakes. They can be releasing seismic waves that can be collected by seismometers, but they are not wrong, there are no tectonic forces at work here, which causes the ice to scrub this scale. In fact, these ice earthquakes may be more closely related to those sorbets or cryoconserves that were collected in Chicago during the recent attack of the polar vortex. When the humid soil freezes, the water inside is expanding and, emerging against the earth around it, it can suddenly crash, creating very localized tremors.

The Antarctic ice earthquakes are a bit different from this; They are still driven meteorologically, but there is no soil involved here, just different layers of ice near or on the surface. However, you could find that cryospheric cheekbones full of ice hit the earthquakes of frost.

studies

A mechanism in which mechanical instabilities are introduced is through the night's ice expansion close to the surface when recovering from the comparatively scorching daytime environment. The team argues that by understanding this process, and quantifying how often this is happening, our general understanding of the destruction of the ice shelf will be improved.

The researchers created a series of seismometers on the McMurdo Ice Shelf in Antarctica during a recent summer, from November 2016 to January 2017. Near a boring and prone part of the fusion of the shelf, they detected millions of small ice quake during that time.

The fact that these earthquakes only appeared to occur during a period of 6 to 12 hours at night, and that they did not occur in areas of dry ice, betrayed their origin: the interaction of several layers of ice during a freezing cycle And daytime defrosting was the only sensitive explanation here. A simple computer model, which simulated the daily transfer of heat to the surface ice and surface ice, confirmed the suspicions.

Although the team only looked at McMurdo, they suspect that this thermally-regulated shaking can be present on all ice shelves that melt on the surface. This suggests that seismometers may be very good to follow the gradual annihilation of these shelves, with the emergence and any increase in the frequency of earthquakes that reveal a greater vulnerability to climate change.


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