stali
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Is it true that earthquakes are not felt in a cave?
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26 votes

Ground motion results due to passage of elastic waves. Now there are different kinds of waves, e.g., P waves, S waves, surface waves, etc. Most of the shaking (and therefore damage) is caused by ...

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Why deep ocean didn't freeze during snowball Earth?
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14 votes

What makes you think Geothermal energy and underwater volcanoes are too weak? The mid-oceanic ridge system alone is 50000 miles long. The mean heat flow at the surface (91.6 mW/m2) has to be ...

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Will a nuclear bomb stop an earthquake from happening?
10 votes

A nuclear explosion in the subsurface will result in ground motion which in theory can trigger an earthquake (due to passage of dynamic waves) if a locked fault has already accumulated sufficient ...

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Locating Missing Airplanes using Remote-Sensing Satellites
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10 votes

Civilian earth observing SAR satellites do not always operate over empty swaths of oceans (specially in the middle of Indian Ocean) in order to save power. They are not designed to track a fast moving ...

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How are Earth's rotational changes due to large earthquakes calculated?
9 votes

Earthquakes, specially those at subduction zones, result in redistribution of mass (as one plate slides on top of the other). This change in distribution of mass causes changes in gravitational field ...

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Is Iceland an example of a hot-spot overlying a mantle plume?
8 votes

Yes, Iceland is an example of a hotspot overlying a plume. The plume has been imaged seismically, e.g., see the Science paper (Figure 3) by Montelli et al. (2004). It is available at http://www....

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Is there a correlation between hot springs and earthquakes?
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8 votes

Hot springs usually exist in volcanic regions or in areas where there are extensive (normal) faults. The water circulates through the fault zones (basically damaged zones with high permeability) ...

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Is earthquake prediction possible?
8 votes

See it is relatively easy to predict where a large earthquake might occur, assuming you have been monitoring deformation for a long enough period, more or less equal to the average inter-seismic ...

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Simulating the earths crust
7 votes

Over longer time scales (hundred thousands to millions of years) deformation of crust can be simulated as a viscous fluid. Basically this amounts to simulating stokes flow (i.e., the math behind the ...

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Similarities between grand circulation solvers and mantle convection solvers
7 votes

The only similarity that they are fluids and therefore NS applies. Actually, to be fair mantle is solid as it allows shear waves to propagate through. However, on geologic time scales it behaves like ...

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How to interpret seismic interferometry data?
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6 votes

It is a differential InSAR image that shows wrapped phase in radians which is a measure of the change in range (or distance) between the ground surface and a (more or less) fixed point in space from ...

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How deep are the cracks in the earths crust at fault zones?
6 votes

Cracks (actually the right word is fault or in some situations rift) can only occur in brittle material and only the Earths upper crust (top 5-25 km) is brittle. The lower crust and mantle are ductile,...

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What is the geothermal potential of a volcano?
6 votes

Volcanoes erupt due to increase in pressure, within the magma chamber (often 3-10 km deep), due to exolusion of volatiles. The magma chamber is usually heated from below. Geothermal plants in volcanic ...

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Change in earth mass since the time of the dinosaurs
6 votes

Earth loses more mass as gases (especially Hydrogen and Helium) escape the atmosphere. Also, the numbers you mention as well as the mass of the air that is lost likely has large error bars associated ...

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Earthquake probabilities
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6 votes

The probabilities are generally based on long term recurrence rates. You can read about the details in the Working Group on Earthquake Probabilities page Earthquake Probability Models. The last ...

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How viscous is the Earth's mantle?
5 votes

The mantle viscosity is likely to be non-linear, e.g., it could be as low as $10^{18} \textrm{Pa}\cdot\rm s$ (over shorter time scales) or as high as $10^{21} \textrm{Pa}\cdot\rm s$ (over longer time ...

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Are craters on Earth covered by vegetation?
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5 votes

Well the oceanic crust get recycled (through subduction), the oldest being only ~200 million year old, and the average, much younger. And on continents it is not just vegetation but dynamic processes ...

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Is it feasible to use depleted oil wells for geothermal production?
5 votes

Geothermal reservoirs are very different from hydrocarbon reservoirs. A geothermal reservoir is made of highly fractured igneous/metamorphic rocks which have low intrinsic permeability. Fluids get ...

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What are the physical upper bounds on the magnitude of an earthquake?
5 votes

Earthquakes involve slip on faults, most of which occur on plate boundaries. Now the width of a fault is usually limited by the downdip limit of the brittle ductile transition. E.g., in case of ...

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How do they know the 2016 Kaikoura (NZ) Earthquake was 'complex', involved six different faults?
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4 votes

You need to see the InSAR data. E.g., see this image which is based on radar data acquired by ESA's Sentinel-1A satellite. For straight faults the pattern is not this complicated. Using such ...

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Meaning of Coupling in Modelling
4 votes

Coupling is used in the context of feedback between various processes. It can be weak or strong. E.g, if you heat a rod it expands mechanically due to thermoelastic effects (strong coupling) but when ...

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What is a Geophysical Model Function (GMF)?
4 votes

In remote sensing you often do not directly measure the variable of interest, i.e., you measure it via some other variable that you can measure (depending on the type of instrumentation). The model ...

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Regarding car exhaust and its possible carcinogenic effects
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3 votes

Yes almost definitely. Its not just gas, but additives, lubricants/oils, coatings, coolant (some of which leaks into the combustion chamber) etc. The full list of known carcinogens is available here. ...

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Calculating the displacement of a fault
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3 votes

The process is carried out by solving an "inverse problem" and there are many ways to estimate the moment depending on the observable. For example if you have some measurements of ground deformation ...

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What tectonic structures delineate the split between the Australian and Indian tectonic plates?
3 votes

The structures are not mature or well defined and deformation was thought to be diffused, i.e., distributed over a large area. Earthquakes such as the M8.6 2012 Indian Ocean earthquake (largest strike-...

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What is the lateral ground acceleration, at the fault line, during a strike-slip earthquake?
2 votes

It can be high but is bounded because the slip velocity on fault (as it slips during an earthquake) is usually of the order of 1-3 m/sec. Kaikoura earthquake (M7.8 strike slip event) had a max PGA of ...

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What is the largest earthquake attributable solely to volcanic activity
2 votes

Earthquakes associated with volcanism or volcanic rifting are typically small. They are caused by over-pressurized magma as it moves around and intrudes into brittle rocks. Sometimes, e.g., in Hawaii,...

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Why do major earthquakes keep happening in Lombok recently?
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2 votes

Yes, it is quite possible to have a number of earthquakes over an extended period of time. The phenomenon is actually quite common. Some famous sequences are: New Madrid in 1811-1812, Eastern ...

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Do the rocks below an active sill go down, or those above go up, or both?
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2 votes

It's both. The rocks above the sill go up, whereas those below it go down. For shallow diking events it's mostly up. This is all based on theory of linear elasticity. People model deformation using ...

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What is the natural replenishment rate of oil?
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2 votes

Almost nil on human time scales. The total estimated reserves (this number keeps changing over time) are of the order of 300E9 m^3. For convenience lets say all of this oil formed over the last 300 ...

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