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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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3 votes
1 answer
337 views

I am trying to write a simple python script for dispersion analysis of surface waves, but I think I am missing something conceptually

I have some simple seismic traces as shown here. When attempting to perform a dispersion analysis using the technique described by this paper, I get the following image. Unfortunately, I cannot for ...
3 votes
4 answers
2k views

What is technically wrong with Wijngaarden & Happer's paper claiming to show that CO2's contribution to surface warming is saturated?

The paper, Dependence of Earth’s Thermal Radiation on Five Most Abundant Greenhouse Gases1, has been reportedly rejected from several major journals. By analysing absorption spectra of greenhouse ...
1 vote
1 answer
42 views

How to compute spherical harmonics coefficients using orthogonality?

I use the lunar gravity model GRGM900C to calculate the gravitational potential across a $360{^\circ}*360{^\circ}$ grid. This calculation follows the equation: $$V(\varphi,\lambda)=\sum_{\mathrm{n=0}}^...
5 votes
1 answer
545 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 ...
8 votes
1 answer
221 views

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 ...
1 vote
0 answers
11 views

hi, any ideas how to convert Rcd and Dst seismic data into SEGY?

any ideas how to convert Rcd and Dst seismic data into SEGY?
2 votes
1 answer
508 views

Does this support Hapgood's Earth Crust Displacement Theory?

I'm no Geologist by any standard but I'm quite intrigued by what goes on below our feet. I came across this article that states there's a new or (confirmed) partially melted layer in the athenosphere (...
1 vote
0 answers
63 views

Why does weaker local gravity cause lower sea level?

The weaker local gravity in the Indian Ocean geoid low (IOGL) causes the sea level to be 106 m below the global mean sea level. Why is that ? "Because of this lower density, the gravitational ...
33 votes
3 answers
13k views

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

I took a tour of a cave in northern California last weekend. The tour guide asked us, "If an earthquake occurred, what would we feel in here?" My answer was, "fear," but she said we would feel ...
1 vote
0 answers
21 views

Question regarding the breakup of India from Eastern Gondwana [closed]

I wanted to ask this question as it relates to a project I am working on. In this "timeline" when India broke away from Gondwana the Indian Plate took a small piece of land from Eastern ...
1 vote
0 answers
125 views

SEG-2 vs SEG-Y file formats

I have limited experience with the different SEG file formats and I was hoping if someone could shed some light on the current preffered file formats used in software applications and for sharing ...
1 vote
0 answers
41 views

What happens to seismic waves reflected back to the surface?

What would be the behavior of seismic waves when it hit the geological media? The waves coming from a source hits different boundaries with different energies, the wave will be reduced in energy by ...
3 votes
2 answers
1k views

what is the best way to actually make the Earth lose heat?

I know that refrigerated air just moves heat around, and creates more by using fossil fuel energy in the process. If we wanted to actually reduce the amount of net heat energy in an area on the ...
5 votes
2 answers
229 views

Why does calcium occur together with felsic rocks and magnesium with mafic rocks if calcium is denser than magnesium?

Felsic rocks contain a lot of sodium, potassium and calcium (and a great deal of aluminum), while mafic rocks consist of a lot of magnesium with iron.... Why is this? Why is magnesium (z=12) in the ...
7 votes
1 answer
738 views

How does the rotation of Earth's inner core influence climate?

In the recent paper published in Nature that sugests a 60-70 years inner core rotation cycle, it is said: Interestingly, the same multidecadal periodicity is also well observed in the Earth’s climate ...
0 votes
0 answers
37 views

Inversion of magnetic data

I am working with inversion of magnetic data and one colleague of my supervisor has said this about subtracting the IGRF for inversions: "”” He needs to subtract a value from them to make the ...
3 votes
2 answers
100 views

With the Earth revolving around the Sun , is there some [invisible] "tail" like Shooting Stars & Comets have?

Shooting Stars & Comets have tails. Here is Example Wiki Image showing Comet with 2 tails : With the Earth revolving around the Sun , is there some [invisible] "tail" like Comets have ? ...
1 vote
1 answer
75 views

What is the reason behind the density being negative value

This is the example density depth functions for various sedimentary sections world wide. But someof the sections marked with red, due to their last term, as i increase the value of z(depth) they ...
5 votes
3 answers
248 views

What criteria determines whether earthquakes are classified as new or aftershocks?

I saw a recent paper where it is claimed that aftershocks can occur years, decades or centuries after the main earthquake. When seismic activity is observed, what criteria determines the ...
0 votes
0 answers
6 views

Input of the relation, source and receptor files into SLB Omega

Is anyone using SLB Omega that knows how to input the source, relation and receptor files that are not using SPS format?
2 votes
1 answer
70 views

Composition of Earth's Core

Is there a list giving an estimate of the abundance of every element of the periodic table in the Earth's Core - possibly differentiating by inner core and outer core? I am specifically interested in ...
0 votes
0 answers
29 views

How to extend the Wyllie time average equation to multiple constituents

I understand the Wyllie time average equation How to extend it to multiple constituents ?
9 votes
3 answers
721 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 ...
2 votes
0 answers
32 views

How to compare sensitivity with lithology between different crossplots?

In the given figure, which is plot of various elastic parameter for sand (blue) and shale(red) sequence. How to find Which crossplot has has greater sensitivity to lithology? Also what is mean by ...
2 votes
0 answers
32 views

Why is static modulus greater then dynamic modulus in limestone?

Generally dynamic modulus is greater then static modulus and experimental data matches that. But in chalcedonic limestone, the static modulus looks to be greater than the dynamic modulus. What could ...
3 votes
1 answer
160 views

What is the reason that some elastic constants are negative?

In this table of elastic constants, indices m = 1 and n = 4 result in negative values. What could the reason be?
2 votes
0 answers
37 views

what is the value of y in additive time series decomposition

I understand the additive time series formula is y = trend + Seasonal + cyclic + residual. But what is the value of y. Is it the the combination of trend, seasonal , cyclic and residual which is shown ...
1 vote
1 answer
83 views

How to connect drillhole from section to the planar view to calculate dip and azimuth?

We have a set of old sections with drill data that I would like to extract and model. I can add sections just fine in Leapfrog, but I have issues with the drill holes, especially connecting the drill ...
11 votes
2 answers
3k views

From how deep in the mantle has any rock ever been brought to the surface? Have scientists found anything they believe originated in the outer core?

I wonder if this is even possible to know.... Do geophysicists and geologists have even a 'theoretical' idea about how deep Earth's churning of its layers goes?
3 votes
3 answers
464 views

How probable is it that Earth's 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 will be the cause of that? If not, then is ...
3 votes
2 answers
111 views

How is the apparent volume affected by particle packing?

This is from paper "The packing of particles" by A.E.R Westman and H.R. Hugill. Here they give result as, "it is evident that if the diameter ratio is unity, ie., the coarse and fine ...
2 votes
1 answer
33 views

Identifying continuously-recording seismic stations

I am trying to identify which stations within the NCEDC network are continuously recording ground motion, and which record only intermittently. I am using obspy's ...
2 votes
2 answers
204 views

Is the global temperature of the earth a physical quantity at all?

In discussions with physically educated among the deniers of the greenhouse effect, it is repeatedly claimed that it is completely pointless to state a quantity such as a global average temperature of ...
0 votes
1 answer
113 views

Do gravity and magnetic field change along a geographic latitude or not?

Along the same geographic latitude does magnetic field change or not, and the same for the gravitational field, does it change along a geographic latitude? Please explain.
1 vote
0 answers
68 views

Necessary Altitude to See Curvature of the Horizon [duplicate]

Many people have asked how high above the earth one must be to see the horizon curve, but I have yet to see a mathematical answer that correlates to the dimensions of the earth. As you rise above the ...
22 votes
12 answers
7k views

How to quickly or easily prove the world is spherical?

A relative of mine has recently introduced me to the modern flat earth theory, which she believes in. Setting aside for the moment that it is ridiculous, and that sending up some balloons with cameras ...
0 votes
1 answer
97 views

What is a general formula for Earth gravity as a function of radius, given a spherical shell model?

I'm trying to derive the formula for gravitational acceleration as a function of Earth radius $g(r)$, given a spherical shell model where each shell has a constant density $\rho(r)$. If I set $r=0$ to ...
12 votes
3 answers
1k views

How do Rossby Waves in the ocean form?

So on land, I believe that one factor in their formation is due to inhomogeneities in surface heating between land and ocean (and also inhomogeneities in surface heating due to terrain effects like ...
2 votes
0 answers
25 views

Where can I get Carbon Capture Storage data?

I need CCS data for Carbon Injection monitoring for a seismic hazard study. Is there any open source data that related Carbon Injection monitoring for example seismic, wells, 1/2/3/4D seismic and etc.
0 votes
1 answer
46 views

Did the 1990 Manjil-Rudbar earthquake postpone a massive earthquake in Tehran?

In this site (published on 6 November 2001) I found the following information: Historical data suggest there is a major earthquake in Tehran every 158 years and the last one there was in 1830. The ...
0 votes
2 answers
76 views

How to calculate latitude and longitude based on relative distance

The coordinates of A on Mars are 125°E and 25°N. The distance of point B is x meters due east from A and y meters due north from A. How to calculate the latitude and longitude of B. Please try to use ...
3 votes
3 answers
1k 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
2 answers
202 views

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.
2 votes
1 answer
72 views

Can a tectonic plate subduct under one plate while another plate subducts under it along the same boundary?

At a triple junction plate boundary there are three tectonic plates meeting. We have plenty of examples of these boundaries on Earth, notably the Afar Triple Junction, Mendocino Triple Junction, and ...
2 votes
1 answer
90 views

Impact Erosion Selectivity In Offloading Radioactive Material

ref : https://science.ubc.ca/news/asteroid-impact-erosion-helped-make-earth-habitable According to the theory of impact erosion, the early crust was presumably much hotter w/ radioactive isotopes (U &...
7 votes
5 answers
5k views

Does the Coriolis Effect affect a wind from East to West?

I'm studying meteorology for a pilot license and there I was taught as a rule of thumb that wind at higher altitudes is approximately turned 30° clockwise to the wind on the surface due to the ...
1 vote
0 answers
72 views

I got this error (segyread: format not SEGY standard (1, 2, 3, 5, or 8)) while converting from segy to su format on seismic unix

[ ~/Desktop/demo ] $ segyread tape=data.sgy| segyclean>data.su segyread: format not SEGY standard (1, 2, 3, 5, or 8) segyclean: fgettr.c: bad first header [ ~/Desktop/demo ] $ 3200+0 records in 6+1 ...
10 votes
1 answer
4k 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 ...
4 votes
0 answers
91 views

Geotechnology: Prove a formula, calculated with unit weights, for void ratio

I don't know where else to post this. I am reading a Geotechnical engineering textbook by B.M. Das, 6th edition. Problem 3.1 is as follows: For a given soil, show that $$e=\frac{\gamma_{sat} - \...
13 votes
2 answers
1k 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). ...

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