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.
72
questions with no upvoted or accepted answers
18
votes
0
answers
225
views
How much heat is transported from the interior to the surface in the form of hydration enthalpy?
Heat is transferred from the interior to the surface through several methods. One is simply the conduction of sensible heat through the crust - I would guess this accounts for most of it. But some is ...
- 1,612
15
votes
0
answers
162
views
What are the ground motion prediction equations for 3-D ruptures?
Ground motion prediction equations (GMPEs) estimate ground motion at any given site due to an earthquake at a distance. There are many such equations, each with different parameters.
Can somebody ...
- 361
8
votes
1
answer
195
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 ...
- 342
7
votes
0
answers
76
views
High-resolution laterolog array tool
Does anybody know if it is necessary to apply corrections to the reading given by this logging tool? Corrections such as bed thickness, borehole diameter, invasion, etc.? If so, is there anywhere I ...
- 171
6
votes
0
answers
75
views
How much does the Earth's center of mass move around?
How much does the Earth's center of mass move around relative to the most stationary objects on the surface?
I'm wondering whether the molten outer core has enough asymmetry to move the center of ...
- 101
5
votes
0
answers
89
views
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 ...
- 271
5
votes
0
answers
206
views
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-...
- 715
5
votes
0
answers
66
views
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....
- 329
5
votes
0
answers
260
views
Did the Three Gorges Dam shift the North Pole by 2 cm?
Numerous sources repeat that, apart from slowing down the rotation of the globe, the Three Gorges Dam caused the geographic pole to shift by 2 cm. For example: https://blog.prv-engineering.co.uk/...
- 51
5
votes
0
answers
81
views
How do you choose appropriate parameters for a lowpass filter when filtering a Bouguer anomaly?
I am trying to filter my Bouguer anomaly data to remove the short wavelength features. I have created a lowpass filter to achieve this, but I am wondering how I can more objectively choose my cutoff ...
- 51
5
votes
0
answers
56
views
How do I generate a Moho depth model from seismic refraction data?
There are several permanent seismograph stations in Eastern Canada that have been recording arrival times for over 25 years. Using refracted Pn arrival times from natural earthquakes I would like to ...
5
votes
0
answers
53
views
Over what scales can we begin to apply fluid dynamics to accurately model properties of the mantle?
Over what size temporal/spatial scales do geophysicists and geodynamicists begin to apply fluid dynamics to model the mantle rather than elastic/plastic deformation theory?
- 380
4
votes
0
answers
78
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
$$e=\frac{\gamma_{sat} - \...
- 141
4
votes
0
answers
90
views
Coriolis parameter approximations
When solving equations involving the Coriolis parameter $f = 2\Omega\sin{\varphi}$, I often see the $f$-plane (constant) or the $\beta$-plane (Taylor expansion) approximations.
If I'm solving ...
- 41
4
votes
0
answers
42
views
What is the electrical conductivity of a liquid Komatiite?
I am searching for previous work that has determined the electrical conductivity range for komatiites at the surface. Does anyone have some values or references?
4
votes
0
answers
49
views
How hot would days get if it were always the solstice in the northern hemisphere?
Imagine the Earth's axis of rotation were to precess in synch with the orbit of earth around the sun so the north pole always pointed towards the sun (same current axial tilt of about 23 degrees). ...
- 41
4
votes
0
answers
85
views
How much would the ground be displaced in a magnitude 11 earthquake?
In a magnitude 5 earthquake, the ground shakes violently and it's often impossible to stay upright. This is caused by about 50-120 cm of displacement of the ground. But how much would the ground move ...
- 141
4
votes
0
answers
49
views
How long for tectonic plates to develop from a planetary, molten planetary surface?
On Earth or an Earth-like planet, how long does it take for a molten surface to solidify into planetary crust, and how long does it take for that crust to develop into tectonic plates?
- 141
4
votes
0
answers
337
views
Cratonization - how did the Archean cratons form?
Before the onset of modern style plate tectonics and the Wilson cycles in the late Archean, it is thought that smaller units of continental crust, called cratons, roamed the oceanic crust over a more ...
user18607
4
votes
0
answers
43
views
What is the minimum temperature difference to drive mantle convection?
The condition for convection to cease is that the Rayleigh number $$\mathrm{Ra}=\frac{g\rho\alpha L^3\Delta T}{\kappa\nu}\lessapprox 10^3.$$ For the Earth's mantle I have seen estimates of $\mathrm{Ra}...
- 441
4
votes
0
answers
56
views
Why an inertial gyro has a frequency and a geostrophic gyro does not?
Inertial flow is given by the balance between Coriolis and centrifugal forces. A geostrophic flow is given by a balance between Coriolis and the gradients of pressure. The frequency of the inertial ...
- 141
4
votes
0
answers
79
views
Seismic data acquisition: reliability of high-bandwidth data
In my research, finding and understanding info relating to the lower end of (conventional) surface seismic data acquisition (i.e. 15 - 1 Hz) is relatively simple. However, when I look at specs for a ...
- 796
4
votes
0
answers
40
views
How do people determine initial ratio of the parent nuclide and daughter product in radiometric dating?
I understand that we have zircon crystals that prevent entering or leaving of nuclide or lead after forming. But how cand we understand what was the initial ratio?
4
votes
0
answers
84
views
What gravitational evidence do we have to counter the idea that oceans are formed when continents sink?
Is there some evidence for this based on gravity anomalies? I think I know how to tell if a mountain or structure is compensated based on bougeur and free air anomalies, but this really has me ...
- 83
4
votes
0
answers
78
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 ...
- 591
3
votes
1
answer
196
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
0
answers
53
views
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 ...
- 755
3
votes
0
answers
59
views
Is it possible for Mexico to have a magnitude 9 earthquake?
Everyone has heard of the Cascadia Subduction Zone and the potential threat it poses. However, I have heard nothing about The Cocos Subduction Zone, even though it caused a devastating earthquake over ...
3
votes
0
answers
312
views
Construction of a drift curve in the well tie calibration and how to interpret it?. Sonic calibration vs checkshot calibration
Good afternoon. Inside the creation of the synthetic seismogram some softwares have the option to run what is called "sonic calibration" or "checkshot calibration". I have some questions:
1)why some ...
3
votes
0
answers
114
views
Do northern lights (aurora borealis) show the same visual activity all along their visible latitude range?
Probability aside regarding their visibility (I did read on Neil Davies Aurora watcher's handbook that probability is highest in the middle of their latitude range called aurora oval, lowering both ...
- 31
3
votes
0
answers
17
views
transition elastic deformation to flow
Let's assume a small (and smooth) vertical deformation of the seabed. If done quickly, I can consider it a vertical force generating an acoustic wave in the water, where every particle of water ...
- 31
3
votes
0
answers
65
views
Difference between landslide waves and earth quake waves
I am new to this field, recently started working on landslide monitoring mainly in signal processing part. I have the following questions?
1.Will each land slide and every vibration have p wave, s ...
- 31
3
votes
0
answers
303
views
How to calculate seismic moment from seismograms?
I was told that
Seismic moment is determined by the observed spectral levels of the receiving waves.
But I don't quite understand what it means.
How is this done in practice? Do you need ...
- 413
3
votes
0
answers
324
views
measuring fracture length and width using PKN and KGD models for hydraulic fracturing?
I am trying to understand PKN and KGD models for hydraulic fracturing. I am wondering why equations for fracture width and length does not include 'breakdown pressure' (pressure at which fracture ...
- 779
2
votes
0
answers
27
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 ...
- 101
2
votes
0
answers
24
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 ...
- 101
2
votes
0
answers
35
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 ...
- 101
2
votes
0
answers
24
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.
- 51
2
votes
0
answers
45
views
Simple Mathematical Equation for the Geotherm
Hi I need a simple equation (polynomial third straight) for a PerpleX simulation to represent the mantle geotherm. The geotherms I have found on the internet so far (unfortunately I don't have the ...
- 1,906
2
votes
0
answers
87
views
What makes special a volcanic pipe to be stable until the mantle?
Comming from this question:
Can we really travel through earth's core?
I wonder what makes special a volcanic pipe to be stable since the mantle through the surface, in comparison to our try or ...
user27958
2
votes
0
answers
38
views
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, ...
- 21
2
votes
0
answers
49
views
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 ...
- 121
2
votes
0
answers
41
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 ...
- 21
1
vote
0
answers
46
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 ...
1
vote
0
answers
44
views
What is the relationship between earthquake risk, magnitude, and distance from the epicenter?
I need a (rough) functional relationship between these three quantities. My initial hypothesis is that the risk $R$ (intended as the probability of a building damage), scales with the square root of ...
- 111
1
vote
0
answers
15
views
Relation between highlands and tidal forces
Could the presence of mountain ranges in continental areas near to tectonic plates boundaries prevent these plates from swaying up and down as a result of vertical tidal forces and plastic ...
- 11
1
vote
0
answers
22
views
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 ...
- 131
1
vote
0
answers
142
views
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?
- 11
1
vote
0
answers
58
views
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 ...
- 111
1
vote
0
answers
72
views
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 ...
- 21