# Tag Info

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### Why aren't seismic stations installed very deep underground so as to pre-warn from earthquakes?

The simple answer is that you can't drill to 50 km depth. The deepest holes ever drilled were to a little more than 12 km, one is named the Kola Superdeep Borehole in Russia, which was a scientific ...
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### Is it true that earthquakes are not felt in a cave?

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 aren't seismic stations installed very deep underground so as to pre-warn from earthquakes?

10 seconds is a worthwhile warning time. The Japanese use it to switch off compressors on gas lines (or open release valves on them), emergency break bullet trains, and in particular shut down nuclear ...
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### If a very huge Earthquake occured anywhere on Earth could waves emerge to come together again on the opposite side?

It is called "antipodal focusing". See for example Antipodal focusing of seismic waves observed with the USArray. We present an analysis of the M-w = 5.3 earthquake that occurred in the Southeast ...
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### Is there any correlation between Grand Solar Minimums (GSM) and earthquakes?

The main proxy that we have of past solar intensity comes from its proven correlation to the number of sunspots, which have been recorded since the invention of the telescope in the early 1600's. And ...
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### If the Bennu asteroid were to hit within a 500 mile radius of Yellowstone National Park, will it trigger a super volcano at Yellowstone?

There is actually an hypothesis that large asteroid impacts can trigger volcanism at the antipodal point, where the seismic energy of the impact focuses. On Earth, it has been suggested that the ...
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### Is it true that earthquakes are not felt in a cave?

There are three main types of waves produced during an earthquake: P, S, and L waves, which stands for Primary, Secondary, and Love. (There was a mnemonic I read many years ago that went P=pressure, S=...
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### If the Bennu asteroid were to hit within a 500 mile radius of Yellowstone National Park, will it trigger a super volcano at Yellowstone?

Maybe but it will depend on the state of the magma chamber under the caldera. If the magma chamber is already under enough pressure and has a super-eruptive quantity of liquid melt in it then the ...
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### Is it true that earthquakes are not felt in a cave?

Googling leads to a very old document: EFFECTS OF AN EARTHQUAKE IN A MINE AT TOMBSTONE, ARIZONA stating that in many cases, mine workers did not notice earthquakes which were felt above ground. A ...
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### Is it possible for Earth to experience Polar Shift?

Is it possible for Earth to experience Polar Shift? Yes, and it has happened before. In the past 80 million years it happened over 150 times. The last time this happened was around 800 thousand ...
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### Why do human populations concentrate near fault lines, volcanoes, etc.?

You're asking Why do human populations concentrate near fault lines, volcanoes, etc.? But the real question is Do human populations concentrate near fault lines, volcanoes, etc.? And the ...
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### What are the distinguishing features of an "artificial seismic wave" (e.g. a large underground explosion)

Several things can indicate that a seismic event is an explosion and not an earthquake. Firstly, the depth of the source. The shallowest earthquakes tend to have a hypocentre that is at least a ...
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### Is it possible that the recent droughts are signs of epic crust failure?

Is it possible that the recent droughts are signs of epic crust failure? No. Even though your 5 points do not make much sense, I'll try to answer it anyway. There are no continental plates. There ...
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### Why do some earthquakes and volcanoes occur within plates?

Crustal plates are not homogeneous, uniformly continuous rock masses with uniform stresses. They are a mixture of rock types with variable stresses and stress concentrations. They are also ...
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### Would the shaking of an earthquake be visible to somebody in a low-flying aircraft?

It depends largely on how deep, or shallow, the earthquake is, how large, and what kind of terrain you're looking down on. Some fairly large earthquakes, magnitude 6-7, can have very little surface ...
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### Will a nuclear bomb stop an earthquake from happening?

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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### Is there a correlation between hot springs and earthquakes?

Yes, there is a correlation. In other words: places with hot springs are more likely to experience earthquakes than places without hot springs. The relationship is scale-dependent in time and space (...
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### Is it possible for Earth to experience Polar Shift?

Yes, it is not just possible, but highly probable. Detailed palaeomagnetic data have revealed how the Earth's magnetic field changes in a polarity shift. In relative terms (time scale inaccurately ...
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### Why did it take so long to discover the volcanic nature of mid-oceanic ridges?

If it weren't for WW2 and the search for German submarines, the discovery of mid-ocean ridges might have waited until satellite based gravimetric mapping in the 1980s. It was the use of fine ...
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### If the Bennu asteroid were to hit within a 500 mile radius of Yellowstone National Park, will it trigger a super volcano at Yellowstone?

Bennu is about 470m diameter, and will impact at a "mere" 11.3km/s. At the impact site it would blast a crater some 3 miles wide and 1500 ft deep, a very respectable impact indeed. The ...
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### Are there any other earthquake magnitude scales other than Richter's?

Earthquakes are measured for intensity and magnitude. Magnitude and intensity are related but measure very different properties of the event. Magnitude is the energy released of the earthquake. It is ...
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### Characterizing earthquakes using accelerometer data

Yes, you can measure seismic energy with accelerometers. Most people do. There are three ways to measure seismic energy: by displacement $x$, velocity $\dot{x}$, or acceleration $\ddot{x}$. Loose-...
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### Is there a correlation between hot springs and earthquakes?

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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### About Earthquakes and their properties

The presence or absence of a large number of massive buildings has no bearing on where and when earthquakes occurs, or their magnitudes; particularly along major fault systems such as the San Andreas ...
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### Where does the 2015 Nepal earthquake rank amongst earthquakes since 1900?

About 80th. I counted the earthquakes of each magnitude on the List of deadly earthquakes... article. If the Nepal earthquake is about M7.8, then it's in the range 69th to 86th on that list: Note ...
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### Nepal earthquake of 25 April 2015

A brief, very simply explanation. The earthquake that struck Nepal on 25 April 2015 occurred in a region with a history of catastrophic tremors. The Indian tectonic plate is slowly moving at an ...
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