Questions tagged [geophysics]

Geophysics is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment.

Filter by
Sorted by
Tagged with
6
votes
2answers
431 views

Are old geophysics textbooks useful?

I have had much success with old textbooks in mathematics. Generally, for any branch of mathematics that I (as a non-mathematician) would like to learn or re-learn, I can buy a classic textbook from ...
7
votes
0answers
89 views

In quasi-geostrophic frontogenesis, what happens if the potential vorticity is negative?

In particular, what happens if the Sawyer–Eliassen equation cannot be solved? I know that a condition for the Sawyer–Eliassen equation to have a solution is $F^2 N^2 - S^4 >0$, which means that the ...
3
votes
0answers
51 views

Capillary rise experiment and obtainable information about the porous medium

I have access to rock core(s) and vacuum saturation chambers as seen in the image below. I can dry the rock core using an oven, measure its geometry and mass. I can place it into the vacuum ...
4
votes
2answers
135 views

Could evidence of a signal from an exocivilization be found in the geologic record?

We know that the current SETI efforts have not found evidence for the existence of intelligent exo-civilizations (XCIV). There also has not been any evidence found of ancient non-human civilizations ...
1
vote
1answer
3k views

What factors affect daily temperature range?

I was wondering if the difference between the low temp and the high temp depended on just the humidity content and the altitude of a place. Or are there more factors? What about the time of year? How ...
8
votes
2answers
1k views

What is meant by phase-change in mantle?

Phase transition usually means changing from liquid to solid phase. But in geology literature we come across transitions from one mineral to other mineral. For example olivine-spinel transition at 410 ...
6
votes
2answers
408 views

How much does the electric current within the Earth' core depend on the axis of the Earth's orbit?

I always thought that the movement of the iron core was caused by the axis of orbit of the Earth. Probably that isn't quite as true as I read, because in the core the iron material undergoes types of ...
3
votes
1answer
260 views

How accurate are the resistivity values from the electrical resistivity tomography (ERT)?

Modern ERT methods/devices can provide 2D resistivity profiles for some terrain. How accurate are the resistivity values in those profiles? Are these some sorts of apparent resistivities and one ...
5
votes
2answers
121 views

What percentage of the earth's surface is covered by 2D or 3D reflection seismic data?

It was recently asserted to me that we have no idea what Planet Earth really looks like below our feet. I responded that (mainly oil-industry) seismic data covers a vast area and so actually we have a ...
1
vote
2answers
96 views

What causes the earth to be a good grounding system?

When working with electricity, rubber shoes are recommended because they prevent current from running through your body. But I've read that usually the earth is more negative charged than positive. ...
5
votes
2answers
4k views

What is (negative) wind stress curl?

I'm currently doing research for a paper in school where we need to research on a university-like level. When I read the paper Causes and impacts of the 2014 warm anomaly in the NE Pacific, I found ...
8
votes
1answer
2k views

How fast does the Earth's inner-core spin?

How fast does the Earth's inner-core rotate compared to the Earth's daily rotation? The inner core is always described as a spinning/rotating solid core while the Earth has a single revolution per ...
2
votes
1answer
191 views

How to correct PSMSL data for GIA?

I have a PSMSL RLR (revised local reference) sea level dataset with records from various tide gauges. Can anyone explain how to correct them for GIA (glacial isostatic adjustment) using the ICE-5G ...
9
votes
1answer
2k views

Earthquakes at plate boundaries

I was looking into tectonic plate boundaries and earthquakes with pictures like these One thing that is quite obvious is that some of the plate boundaries have very thin zones of earthquakes, ...
3
votes
4answers
451 views

What is the origin of oil?

Most people may believe that oil comes from dead plants and animals, but there are alternative theories that are known as Abiogenic Petroleum Origin. If oil in generated in this manner it could mean ...
2
votes
3answers
2k views

Why is the density of Earth higher at the core

If gravitation decreases as we approach the core and if density is a function of gravity we should expect a void core. Unless the accretion disk was formed starting with the objects of highest mass ...
5
votes
1answer
966 views

Open source seismic refraction processing

What I am in search of is an open source tool to pick first arrivals, plot travel-time curves, and perform simple velocity modeling. I am experimenting with seismic refraction to identify shallow ...
7
votes
2answers
526 views

How did Great-Britain separate from France?

Looking at continental plates both France and GB lie on the Earasian plate. Now those plates moves and created our continents of today out of Pangea. But a lot of pictures shows that France and GB ...
1
vote
1answer
196 views

What is meant by Monte-carlo simulation? (would like an elaborated answer with some references) [closed]

I have come up with simulations which involves monte-carlo method that I am not fully aware of. I would be very happy if someone can help me with some references to read and learn.
-1
votes
2answers
88 views

Can the sealed bottle garden be called a perpetual motion machine? [closed]

I was not sure just where to ask this question, but I was wondering if the sealed bottle garden be really called a perpetual motion machine. http://www.dailymail.co.uk/sciencetech/article-2267504/The-...
5
votes
1answer
7k views

What is difference between divergent boundary and hot spot?

As I know, both divergent boundary and hot spot are formed by rise of magma of convention, but divergent boundary is a line and hot spot is a point, is there difference between 2 kinds of rising magma?...
3
votes
2answers
168 views

Conditions at the bottom of a VERY deep hole

I'm a science fiction author looking to describe what conditions might be like at the bottom of a cylindrical shaft ~ 30 meters across and ~ 35 km deep. It's located somewhere on the edge of ...
2
votes
0answers
40 views

Phase of S2 constituent in tidal prediction

I ran the ETERNA code for the prediction of tidal gravity at some station. Then I use Fourier analysis to recover the amplitude and phase of the S2 constituent. As I understand, the phase of the S2 ...
5
votes
1answer
409 views

Global scale seismology experiments / observations disproving flat earth conspiracy?

Recently I've taken an exceptionally unwise interest in the beliefs on conspiracy theorists, in particular flat earthers. Flat earthism has been trending heavily lately and indeed is undergoing some ...
3
votes
1answer
111 views

Do our continents lay on the mantle because solid silicon dioxide is less dense than its liquid form?

I don't know whether quartz behaves like ice or not, but could it be because silicon dioxide, which the continents are made of for a big part, is less dense - so the continents lay on top like ice on ...
6
votes
1answer
179 views

Why is ground water rising on these forest rings?

I am seeking a physical explanation for this; There is huge amount of such a Forest rings in Earth; (Link to Google Maps to one ~400 m Ring) They range in diameter from 30 metres to 2 kilometres, ...
5
votes
3answers
9k views

Does a mountain top have higher gravity than a nearby sea-level surface?

Regardless the latitude and centrifugial 'force' is the gravity on mountains higher or lower than at sealevel? Gravity is depending on the radius to the centre and the mass. Now if you are on a ...
12
votes
5answers
2k views

Are there water molecules in the oceans which will almost never fall down as rain?

Some oceans are very deep. But is there also current (convection) deep in the ocean so that all water molecules will ones be evaporated and fall down as rain or is it very quite at the bottom so some ...
1
vote
1answer
447 views

Will the Earth's core cool? [duplicate]

I am doing a school project and need to know... Will the Earth's mantle or core ever cool? If so, how? Thank you!
13
votes
1answer
592 views

How is known that the Earth core is solid?

As I know, the Earth core is solid. This is known, because it conducts also transverse waves, while liquids conduct only longitudinal waves. But, how was it found? The inner core is in the outer core,...
10
votes
1answer
242 views

Carbonate reef not horizontal in seismic section?

Carbonate reefs usually appear as homogeneous bodies surrounded by sediment layers in seismic reflection data, but in the figure below the high amplitude reflection from the top of sediment (layer 2 ...
5
votes
1answer
568 views

How does Vertical Electrical Sounding Work?

I recently conducted a brief training exercise with VES equipment, although it had to be called off due to rain. I can't help but wonder about the basic physics of it, why is it that increased ...
4
votes
1answer
391 views

Why is fluid pressure in a fractured rock reservoir only dependent on hydrostatic pressure?

Why does lithostatic pressure not play a role? (or does it?)
4
votes
1answer
196 views

Gravitational Anomaly of a subsurface body

How does the gravitational anomaly measured at the Earth's surface and produced by a subsurface body depend on its depth and on the density contrast of the body relative to its surroundings?
8
votes
2answers
2k views

How viscous is the Earth's mantle?

I'm posting here to get some more expert information based on this question. If the Earth were to stop rotating, removing the centrifugal force causing the equatorial bulge, how long would it take ...
12
votes
1answer
825 views

What's the distance between the center of mass and geometrical center of Earth (CM-CF offset)?

I asked the same question on Physics StackExchange site. I now know that there are several types of "center" and I can tell, I'm interested in the CM-CF offset (CM = geocenter, CF = center of figure). ...
3
votes
1answer
609 views

Seismic data processing software

For processing seismic data, why is Seismic Unix so important? What distinguishes it from other seismic processing software like GLOBE Claritas or Omega? Is it argued that processing capabilities are ...
2
votes
0answers
92 views

SeismicUnix - Finite Difference Migration [closed]

I'm trying to apply sumigfd on simple.su data which is used in the John Stockwell course in geophysical image processing - in the Migration chapter on page 85. I have not had any success because the ...
6
votes
2answers
511 views

How bad is geo-engineering?

It is just curiosity that forced me to ask this question. At some point in time, if we can't control global $\sf{CO_2}$ emissions, temperature will increase until a tipping point and it will be a ...
8
votes
1answer
138 views

Regarding velocity of P/S-waves

I feel like I am missing something blindingly simple, but I am curious about something. We are given the velocity of a P-wave as $v_{p} = \sqrt{(K+\frac{4}{3}μ)/ρ}$. So I am to understand ...
10
votes
1answer
4k views

Why is the South Pole colder than the North Pole?

This question popped into my head because I am designing a fictional world map, and I was wondering what factors influence the amount of ice at poles. I want to know why there is much more ice ...
6
votes
1answer
2k views

Compute direction of gravity vector

As I understand to compute vector of gravity not saficient to compute normal to elipsoid, but we need to computer normal to geoid (by definition geoid is a surface to which the force of gravity is ...
11
votes
4answers
6k views

Does gravity differ from place to place on Earth

Does a particular object have the same weight on every part of Earth or does it vary?
3
votes
3answers
253 views

How probable is is that earth magnetic field will change 180 degrees at once?

Today the Earth's magnetic field is moving a little bit. But is there going to be a point where the field suddenly radically changes direction? If so what is the cause of that? If not, then is the ...
2
votes
1answer
2k views

Why are oceans so deep?

Some areas of oceans are about 11 km deep. Is it because continental plates were moving away because of troughs in the middle from where new rock is formed? If so, why did it become deep? If not, what ...
4
votes
1answer
155 views

Is there a differential angular rotation on Earth?

I asked a question about solar day difference between two latitudes on the same longitude here on the Earth surface. The answer was clear due to constant angular rotation time is the same. Tangential ...
6
votes
2answers
950 views

Is there a time difference between two points at the same longitude but at different latitudes?

Assume we have two cities A and B both at the same longitude (say $45^{0}$ E) but at different latitudes say $8^{0}$N and $90^{0}$ N. Can we get a time difference between these two cities. I raised ...
9
votes
2answers
667 views

Terrain correction for gravity data using Nagy, 1973

I am working with an algorithm for terrain correction of gravity data. I am using Nagy, 1973. However, I could not get the results I need. So, this is the problem. I have this function where x,y,z ...
9
votes
1answer
197 views

What is the current status of geophysical global cooling theory?

Plate tectonics effectively rubbished the theory of geophysical global cooling as a means of explaining many surface features on the Earth. However, this wiki says that the same process is responsible ...
-6
votes
2answers
307 views

Next Ice age may be unavoidable

During the warm period before the most recent ice age, 120,000 years ago, roughly half of the Greenland ice sheet melted.This is thought to have been the cause of the last ice age. Question: If this ...