# 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.

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### Why were the Interglacial periods in the early Pleistocene spaced about one million years apart, but recent ones only 100,000 years apart?

The Teglen (or Tiglian) interglacial period began after approximately half a million years into the Pleistocene, and the next interglacial (Waalian) occurred about a million years after that... But ...
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### Help with question 1c please [closed]

Help with question 1c and 4b please
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### Least equatorial ( and tidal) bulge consistent with modest amounts of water in polar regions

In World Building I asked a question about the climate of an hypothetical planet. There Vogon poet said that Everyone above 10° latitude will be in permanent drought Considering that there were no ...
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### Is there any free indexed journal that Geoscience students can publish?

I am planning to publish a paper related in Geoscience/Geophysics/Seismology within scope of Machine Learning/AI in particular. Is there any Journal that provide free article publishing for ...
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1 vote
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### Under which conditions would you see the MOST lake effect precipitation?

It's well known that the Great Lakes produce large amounts of precipitation in the Fall. When cold polar air moves over the lakes it causes large amounts of relatively warm moist air to rise, ...
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### Is it possible for tsunamis to occur on deep water planets?

Assume a water planet with an ocean depth of about 200-500 km. Would a very strong ground-quake happening at the very bottom of the planet's ocean floor be able to cause a large tsunami to rise up to ...
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### Why is some ocean on continental crust?

While most ocean crust is formed from oceanic plate formations there are areas of the ocean (much of the Gulf of Mexico, Eastern US coast, North Sea, Arabian coast of India) which appear to be ...
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### Can a planet have both magma volcanoes and cryovolcanos?

I know that the Jovian ice moons have been speculated to have cryovolcanos. I was thinking of the ice planet of Hoth from Star Wars and in one of the video games; it has regular volcanic activity. ...
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### Why are the supposed-to-be results of collision and/or subduction formed in an area where collision and/or subduction didn't happen?

Please correct me if I have said something wrong, as it might be the answer to my question. Also, these are all the things that I've learned through self-studying, so I might have been mislead. ...
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### Seismic velocity relations

I do understand why the seismic velocity decreases with temperature and increases with pressure, but I am not really familiar with the relationship between the velocity with Poisson's ratio. I ...
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### What is the purpose of wavelet extraction from the seismic trace?

I would love to know what exactly we can do with the extracted wavelet. What kind of information extracted wavelet can contain?
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### Can pumping water into the aquifiers reverse the sinking of cities like Jakarta?

Indonesia decided to relocate the capital, in part due to environmental struggles facing Jakarta: one of the fastest sinking cities in the world due to the over extraction of groundwater Source: ...
1 vote
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### What is a Poisson solid and what affect does it have on p and s waves?

What is a Poisson solid and what affect does it have on p and s waves?
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### What are these undersea lines all around Hawaii?

On Google Earth, there are these radiating undersea lines all around Hawaii: Here with a bit more contrast: Unlike the other lines, they are pointed away (or toward) a single place. What are these, ...
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### Could a nuclear explosion in the Atlantic Ocean during the hurricane season trigger a hurricane?

I am wondering if denotating a nuclear bomb in the Atlantic Ocean during the hurricane season could trigger a hurricane. For example, say that a 100-megaton bomb was loaded onto a ship and that ship ...
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### On geostrophic wind. How can the Coriolis force cancel out the pressure gradient force when they are mutually perpendicular?

If we are in Northern Hemisphere and there is a point where there is a high pressure, denote it by H, and there is a point where there is low pressure, denote it by L, (for simplicity assume them to ...
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### Ways of detecting underground bodies of water

I saw one way to achieve this using the magnetotelluric way, but I need some solid fundamental way to understand it. Any book recommendations would be appreciated.
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### Airborne geophysical survey in steep and undulating terrain. What is more important, energy conservation or orienting lines wrt to geology and why?

I am trying to design a cost and energy efficient aerial survey and have come up against the question, 'do we have to fly straight lines perpenducular to geology?' as not doing so could make for a ...
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### Is there a way to calculate crater depth?

For the sake of the example, let's assume a crater on Earth roughly twelve miles in diameter. Is there a way to calculate a range between how deep or shallow this crater would be?
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### Predicting rock type from seismic processing

In reflection seismology, we create a source with an airgun and then use receivers to register acoustic waves (an approximation) at the surface. From these measurements, we can predict a velocity ...
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### Can "meanders in meanders" form naturally?

I recently rafted the San Juan river in Southern Utah, which flows into the Lake Powell reservoir. When the water levels in Lake Powell were very high, it extended far upstream into the San Juan ...
1 vote
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### Specific cases of 528 Hz harmonics that appear in nature that are not wideband radiation or noise? [closed]

I was looking up something about the 528 Hz frequency that people like to talk about, and some of the evidence used to support the idea seemed a little irrelevant. Like, of course the sun emits 528 Hz ...
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### Taking into account the decay products of transuranic elements, are the world's uranium reserves growing or shrinking?

I was talking to a friend of mine who is an environmentalist like me but not a big fan of nuclear power and she told me it was not a good option in the long run because of the decay of uranium. Of ...
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### Coriolis parameter approximations

When solving equations involving the Coriolis parameter $f = 2\Omega\sin{\varphi}$, I often see the $f$-plane (constant) or the $\beta$-plane (Taylor expansion) approximations. If I'm solving ...
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### Elevation accuracy to distinguish maximal gravity anomaly of a sphere with 50% hematite

Question: What is the accuracy required in elevation to distinguish the maximal gravity anomaly of a spherical 50% Haematite (Iron mineral) ore with a radius of <...
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### Do greenhouse gases absorb and re-emit photons or reflect them diffusely? Or both? (CO2, CH4, H2O, N20, HFC-134a, etc.)

Also, would it matter if a particular type of greenhouse gas molecule reflected rather than absorbed and then re-emitted light? Would its GWP be higher or lower? Perhaps this is more of a pure ...
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### What are the boundary conditions for Navier's Equations of motion in seismic?

Navier's equations of motion in seismic have 3 solutions, according to how it is resolved (boundary conditions): for Vp (compression waves) for Vs (shear waves) for Vr (Rayleigh waves) I know the ...
1 vote
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### Can Hydrocarbons be beneficial? [duplicate]

Do these “fossil fuels” underground help maintain homeostasis in microbial ecosystem or aid in the growth of flora etc? Or are these substances: coal, animal remains and natural gas detrimental even ...
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### Range of frequencies of the Schumann resonance?

Crossposted at Physics SE As the surface-ionospheric gap acts as a resonator for electromagnetic waves, it should have several harmonic values from the base, fundamental frequency of 7.83 Hz. These ...
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### How to interperet audio magnetotelluric results?

I'm newbie in filed of Geophysics science. I will be grateful if you could help me to understand this chart what does line 12 or Line 11 mean? what about line15-14? How to identify the depths? what ...
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### How long do geostrophic currents last?

My professor posed this question, without any relevant material. I suppose the currents last until the density gradient is neutralized, but I can't find any literature nor articles on this, regarding ...
1 vote
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### Understanding the EM survey results

I have contour maps showing conductivity and in-phase data from an electromagnetic survey done on a ground, where, supposedly, an underground sewer system is running horizontally across the survey ...
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### What affects where a terrain will be rocky or grassy?

I’m working on a terrain generator and I now need to color the terrain to be rock, grass, or snow. Ignoring snow for now, at first I thought I’d make flatter areas grass and make steeper areas rock. ...
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### What is the electrical conductivity of a liquid Komatiite?

I am searching for previous work that has determined the electrical conductivity range for komatiites at the surface. Does anyone have some values or references?
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### How hot would days get if it were always the solstice in the northern hemisphere?

Imagine the Earth's axis of rotation were to precess in synch with the orbit of earth around the sun so the north pole always pointed towards the sun (same current axial tilt of about 23 degrees). ...
1 vote
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### Why should wellbores be supported by pressure, but not mine tunnels?

I recently read about safe mud window - it states that the mud pressure in a wellbore should be high enough to prevent well collapse, and should not exceed the formation's fracture pressure. But ...
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### How much would the ground be displaced in a magnitude 11 earthquake?

In a magnitude 5 earthquake, the ground shakes violently and it's often impossible to stay upright. This is caused by about 50-120 cm of displacement of the ground. But how much would the ground move ...
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### When will the Earth lose its magnetic field?

Mars lost its magnetic field 4.5 billion years ago according to this article: Mars lost its global magnetic field during the time of this heightened activity. After 500 million years, the Martian ...
1 vote
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### Quality control in Seismic Acquisition - shot offset shift

I have a problem with seismic data where the minimum offset of the shot is not centered at the nearest receiver, this shift can be for 3 traces 2 or one and maybe more in the two sides !! So is there ...
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### IGRF -13 Geomagnetic field, Calculating Partial Derivatives of Legendre Polynomials

I have been trying to implement the IGRF-13 geomagnetic model on my own in C code. I have followed the equations from the website below and I am getting correct results for the B$_{\phi}$ and Br ...
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### Can a planet be heated by the green house effect to a temperature higher than that created by its incident and net absorbed, peak external radiation?

In that the green house effect, as caused by various atmospheric gases (e.g., H2O, CO2, CH4, etc), acts as an insulating layer which only retards the escape of heat from the planet, it would seem that ...
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### How much of all current energy on earth arrived as sunlight vs. as kinetic energy during formation?

For example, sunlight captured by plants would count in the "arrived as sunlight" category, whilst heat energy in the core of the earth would count in the "kinetic energy during ...
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### How do the Andes get so high?

I'm interested in the limiting factors on the height of mountains. There is a very good explanation at https://www.quora.com/How-tall-can-a-mountain-become-on-Earth-Neil-deGrasse-Tyson-says-Mount-...
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### Conversion of SEG-Y relative to MSL

I am working on the conversion of CSF file from SonarWiz into SEG-Y data. However, it comes back always related to the Sensor depth/altitude and never to the MSL. I have tried changing the bytes from ...
1 vote
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### What would happen if the inner core bulged and moved a tiny bit?

The inner core is solid only because of the very high pressure of the outer core and mantle . Say, if the inner core moved a teeny tiny bit would some of it liquify and melt? Or does it stay solid? ...
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### Where can I find an anisotropic PREM-like model for Earth's interior?

So, I just discovered PREM (the Preliminary reference Earth model) which models the density distribution of matter inside the Earth to any depth. The PREM is very convenient but since it only depends ...
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### Hypothetically, in the near future, could gas hydrate pingos erupt?

Could gas hydrate pingos erupt? If so, how quickly? And how much CH4 could they release? I'm sorry if the questions sounds silly. I'm new here and I don't know much about gas hydrates and oceanography....
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### Is it possible to kickstart an hypothetical frozen earth with 0.6 ice albedo to an earth with an atmosphere, with just the sun at current distance?

Phase change of water at different pressures and temperatures tell us that with no atmospheric pressure 200 Kelvin (minus 73 Celcius) is enough to turn ice into vapor directly Wouldn't that suggest ...
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### Would it be possible, from the earth’s creation or during its various geomorphological changes, for all the following hypotheses to be probable?

I’m designing a fictional world setting for a game, and I would like to know whether it has a relative coherence based on science. (Don’t mind if it is an almost improbable scenario). Would it be ...
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