17
votes
Why is the temperature between the earth core and surface not distributed linearly?
The temperature does indeed increase with depth, something that is a problem in deep mines or deep drilling, but a benefit for geotermal heating. The heat originates mostly from radioactive decay, but ...
- 5,936
13
votes
Are the oceans rising or the continents going down? How can we know?
To the best of our knowledge, sea-level is rising because the volume of water is increasing.
There is substantial local variation in sea-level change; it's falling in some parts of Canada. But of the ...
- 10.9k
13
votes
How plausible is it that "a portion of the ocean's floor" could suddenly be "thrown up to the surface" as described in this Lovecraft story?
Generally the Earth's geology moves very slowly, ... very slowly. When people use the term geological time scales they mean a very long period of time, usually in the millions of years. In volcanic ...
- 23.2k
12
votes
Accepted
Gaps in locations of volcanos (Peru & Chile)
As you said, the Andean belt is divided into four segments, usually called the northern, central, southern, and austral volcanic zones (NVZ, CVZ, SVZ and AVZ, respectively; your map lacks the AVZ). ...
- 6,990
10
votes
Are old geophysics textbooks useful?
Mathematics and computer science are exact sciences. If something is discovered and known, it is not wrong. With time, there may be better or new ways of doing something, but the old stuff is still ...
- 22.9k
10
votes
How plausible is it that "a portion of the ocean's floor" could suddenly be "thrown up to the surface" as described in this Lovecraft story?
Very implausible.
If your sailor is actually in the middle of the ocean, there are several kilometres of water underneath. Nothing that we know of can uplift kilometres of rock overnight, at least ...
- 22.9k
9
votes
Accepted
Simulating the earths crust
I am afraid that you aren't being specific enough to really answer your question: What about mountain chians valleys and hills are you interested in? There are simple and complex models dating back ...
- 6,446
8
votes
What is the reasoning behind the statement "Faulting will occur along the plane where the shear stress is the highest"?
This statement is known as the Wallace-Bott hypothesis. It is mostly valid for reactivated faults rather than fresh rocks(where cohesion comes into play). It says that the slip in a fault plane will ...
- 341
7
votes
Does volcanic activity fluctuate?
The previous answers contain important facts, but neglect recent discoveries. As tobias47n9e says, the increase in observed output over time is an observational effect. As kaberett explains, if you're ...
- 2,583
7
votes
Accepted
Predicting earthquakes using disturbances in DTH TV transmission
Earthquake prediction have been discussed before in this forum and is rather dispiriting. Distortion in transmitted signals could be an early indication of earthquake, but seismometers (geophones) are ...
- 5,936
7
votes
Simulating the earths crust
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 ...
- 2,381
5
votes
Accepted
Can the sealed bottle garden be called a perpetual motion machine?
There are no perpetual motion machines.
So when you think you've found one, you need to ask a couple of questions, because there will always be an answer to at least one of them.
How is the ...
- 4,090
5
votes
Accepted
How to define the force at the base of an oceanic crust
Your approach of adding all the forces together is correct. You have a mistake in in the solution of the $F_{oc}$ integral, though.
You forgot to integrate the terms $\rho_{w}gh_{w}$ and $-\rho_{oc}...
- 413
5
votes
Accepted
How to calculate hydrostatic equilibrium?
I am assuming you are asking for the case of sea level being 200m higher and in isostatic equilibrium. In that case we can make use of Airy's isostasy model: https://en.wikipedia.org/wiki/Isostasy#...
- 413
5
votes
What are some of the strongest theories against the existence of mantle plumes?
As mentioned, the theory is so vague that it's impossible to falsify nor support it with present methods and data. Geologists can learn something about the limitation of tomographic models in this ...
- 5,936
4
votes
How can we determine the size and composition of Earth's inner core?
In 1906, Richard D. Oldham found that the increasing speed of seismic waves with depth within the Earth holds only down to 2890 km below the surface. Deeper than that, the mechanical waves (sound) ...
- 1,673
4
votes
Are the oceans rising or the continents going down? How can we know?
While there are specific cases of continental sinking, I think this needs to answered on a global scale in which continental lithosphere is significantly more buoyant than 1) the mantle and 2) oceanic ...
- 6,446
4
votes
Flexure of a viscous lithosphere - derivation
The problem with my derivation is I am not sure if it correct and I do not have a way to check it.
Try dimensional analysis to check your solution. Is your solution consistent with dimensional ...
- 3,790
4
votes
Accepted
Is there a differential angular rotation on Earth?
The Earth's atmosphere rotates at more or less the same rate as the Earth as a whole. Note my use of "more or less". That does not mean exactly the same.
The air does rotate pretty much at the same ...
- 22.6k
4
votes
Accepted
why continents do not subduct
It is continental crust which hs the greater buoyancy, so when it meets another plate of continental crust neither can subduct. Instead, they collide, crumple and fold, making them thicker and higher. ...
- 4,537
3
votes
Accepted
How much change has there been to the shape of plate boundaries over geological time?
I am not sure if you are actually asking about Tectonic Plate boundaries, or the boundaries of continents, which are often described a puzzle pieces when teaching continental drift due to the way ...
- 46
3
votes
Are old geophysics textbooks useful?
Every textbook written between about 1930 and say.....now, is pretty useless for your purposes. You'd be better served by watching many of those slick, university produced video lectures. They are ...
- 2,783
3
votes
Simulating the earths crust
There are several codes which can probably model what you seem to describe. A few that come to mind (in no particular order) are Underworld, Elefant (C Thieulot) and Elvis (T Gerya). The choice really ...
- 179
3
votes
How can we determine the size and composition of Earth's inner core?
The previous answers are correct in that geophysics and crust-mantle samples are the main tools for sorting out the composition of the core.
In addition, don't forget that meteorites are the solid '...
- 14.1k
3
votes
How plausible is it that "a portion of the ocean's floor" could suddenly be "thrown up to the surface" as described in this Lovecraft story?
Putting a piece of oceanic crust on land is an existing geological process called obduction. However, it is not a sudden process, but rather a very slow one.
Now, there is one process that can lift ...
- 6,990
2
votes
Does volcanic activity fluctuate?
It's reporting bias, and over longer time spans there's a preservation bias as well since a small eruption like Ruapehu 1995-96 will not show up in the fossil record at all after a few hundred years ...
- 4,250
2
votes
Does volcanic activity fluctuate?
I would just like to quickly emphasize the forward-mindedness of lunar and additional celestial mechanics when looking at fluctuations in global eruption rates. Since it isn't just the oceans which ...
- 171
2
votes
Could the Earth's core lose its heat?
The earth produces 20TW[1] of thermal energy from radioactive decay in the mantle. This is the amount of warmth that the earth generates, so it should give us a ballpark idea of how much heat we would ...
- 21
2
votes
Predicting earthquakes using disturbances in DTH TV transmission
There already exists at least one method that attempts to use electromagnetic precursors to earthquakes; it actually tries to detect electrical currents running up through active faults, explained by ...
- 121
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