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1 vote
1 answer
35 views

Estimation of velocity of the wave from seismic trace

How can seismologists estimate velocity (on the different layers) of the wave propogated through the earth , only from given seismic trace(s) ?
2 votes
1 answer
79 views

How to quantitively compare two seismic waveform data?

Our group has built an Arduino-based device with an MPU6050 to act as our seismometer for our project, with the data being displayed on Amaseis. Our proctor demands that we quantitively assess its &...
0 votes
0 answers
43 views

Zoeppritz equations

I have a question regarding zoeppritz equations. The equations from Telford are as follwoing: When trying to put in a matrix form, by converting amplitudes to reflection and transmission coefficients,...
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?
1 vote
0 answers
158 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
42 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 ...
2 votes
1 answer
59 views

If deterministic wavelet is better for well ties , why do people use statistical wavelet too for wellties?

Synthetic trace generated with deterministic wavelet gives a higher correlation with real seismics. Though it's more accurate for seismic well ties than statistical wavelet, but there is always an ...
2 votes
1 answer
4k views

Can large earthquakes happen few times at same place(in days)

I want to know if large earthquakes can happen twice in the same place? I live in Istanbul/Turkey. In Canakkale/Turkey too many earthquakes happen for days! I know it is normal for this region but 4.8 ...
3 votes
2 answers
155 views

Is it reasonable to approximate the swinging building (base of the building) during an earthquake to a simple harmonic motion?

I am thinking of making a model of swinging building during earthquake and study the methods to minimize the swinging. So does it even makes sense to approximate the swinging buildings (the base of ...
6 votes
2 answers
125 views

How to produce random numbers from seismic data?

I have read that the University of Chile uses seismic data to produce random numbers. (https://random.uchile.cl/randomness-beacon). Does seismic data real have randomness and if it so, which ...
5 votes
1 answer
116 views

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?
3 votes
2 answers
2k views

Seismic dispersion: What does it really mean and what causes it?

Body waves (to some extent) and especially surface waves show dispersive characteristics during propagation. In Dr. Christopher Liner's book [Elements of Seismic Dispersion (2012)], this phenomenon is ...
3 votes
1 answer
108 views

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 ...
5 votes
1 answer
167 views

Is there a seismic discontinuity between the lithosphere and asthenosphere?

I've been learning about seismic discontinuities, mainly the 5 defined ones - Conorod discontinuity, Mohorovicic discontinuity, Repetti discontinuity, Gutenberg discontinuity, and Lehmann ...
3 votes
2 answers
1k views

Travel Times for Seismic Wave Types - Why reflected t-x plot curves

I do not understand how the reflected wave in a seismic survey has a steepening slope (slows down) Please bear with me as I lay out my thoughts because I feel like I can grasp all of this except this ...
4 votes
0 answers
35 views

Seismicity associated with post glacial rebound

Allied to the question: Why is relative sea-level falling in Hudson Bay?, where the surviving answers mention post glacial rebound. Is seismicity associated with post glacial rebound and if so what is ...
1 vote
0 answers
40 views

Are there specific layers in the subsurface that come before gas or oil?

Currently, I've started working on a geophysics project. More specifically, I'm trying to find gas and oil reservoirs in SEGY files using deep learning. I've been reading about seismic reflection ...
1 vote
0 answers
60 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 ...
6 votes
1 answer
1k views

What is the relationship between raw seismic data, CMP Stacking, NMO & Machine Learning

I recently joined a geophysics project to assist with some of their machine learning modeling but am trying to gather the domain knowledge required to participate. Something I don't quite understand ...
1 vote
0 answers
34 views

Preconditions for stacking

Some of the requisite for stacking is that the noise and amplitudes need to be uncorrelated. Can someone explain to me why? Also is there a drawback for stacking?
1 vote
1 answer
88 views

Q factor estimation from VSP

in seismic data processing there is a step of calculating the absorption represented By Q value which is Q factor , how we can estimate it from VSP ! thank you.
1 vote
0 answers
91 views

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 ...
1 vote
0 answers
23 views

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 ...
2 votes
1 answer
78 views

Recent high seismic activity in Europe

It seems that Europe and the Mediterranean Sea have had high seismic activity in last six months. Major events which I remember are: 2020 Aegean Sea earthquake, magnitude of 7.0 Mww 29 December 2020:...
4 votes
1 answer
215 views

wavelength of seismic wave with a gaussian source

I want to know how to get the wavelength/frequency of a seismic wave, if I only have a Gaussian source and the velocity (c = 4000m/s) of a medium given. e.g. for a Ricker wavelet it would be easy to ...
7 votes
1 answer
9k views

SEGD and SEGY recorded data

What is the difference between a segd recorded data and a segy recorded data and can we convert from segd to segy and vice versa?
1 vote
1 answer
142 views

What would be the phase shift and polarity of a seismic wave upon reflection

What would be the phase shift and polarity of a seismic wave a) when it hit the free surface b)when the free surface reflection goes down and hit a reflector and returned to the receiver placed on the ...
1 vote
1 answer
108 views

Where can I find broadband seismic reflection data?

or what type of companies should I contact to ask for the data? This data would be produced from Seismic Vibroseis survey trucks which are mostly used to locate oil and gas. I doubt most oil and gas ...
4 votes
0 answers
226 views

Beam forming FK analysis of a seismic wave

So after reading alot of literature on source localization, I found out that FK analysis is one of the most widely used methods to determine source location without explicitly calculating the ...
2 votes
4 answers
4k views

Why is a mild earthquake often mistaken as dizziness or vertigo?

Is it due to the longitudinal nature of the seismic waves? When a heavy bus or truck goes by at high-speed, the shaking in nearby ground is not mistaken as dizziness, rather the feet and body feel a ...
1 vote
0 answers
60 views

How does uplift lead to onlapping?

I read in a paper that: Interpretation of 2-D seismic lines shows the lower to middle Patchawarra Formation onlapping onto paleostructural highs at approximately 270 Ma and again at 273 Ma, ...
2 votes
3 answers
273 views

stretch phenomena after NMO application on seismic data

after the NMO application we have stretch for far offset , i read a lot of articles but i can't have a complete idea how this phenomena is really created ! any one have a rich explanation ?
1 vote
1 answer
999 views

How do we know the speed of S-waves (shear waves) in the Earth's inner core? Has this been measured?

Wikipedia's Seismic wave includes the plot below of the speed of S and P waves as a function of depth in the Earth. In the region of the outer core the speed of S-waves or shear waves is shown to be ...
2 votes
2 answers
2k views

converting segd data to SU format using seismic unix

I tried to convert segd format to su format using seismic unix by below command: segdread tape=1.segd > 1.su but I have an error: ...
8 votes
2 answers
375 views

Cross-line fold of a towed-streamer survey

On page 29 of the book 3D Seismic Survey Design by Gijs O. Vermeer, Vermeer says that the equation for a maximum fold in a 3D survey is the following: $M = M_i \times M_c$ where $M_i$ is the inline ...
2 votes
1 answer
153 views

Using an accelerometer as a geophone to conduct a seismic survey

I am doing a capstone project for a sensor systems course and I would like to write a python program to acquire, process and present seismic data like that of seismic surveys. Is it possible using ...
3 votes
1 answer
2k views

Why do P waves have a higher velocity in the lower mantle than in the core even though the core has a much higher density?

I've just started teaching 9th grade Earth science and my students and I have noticed something about P and S wave depth vs velocity graphs. In the typical graph, eg: https://www.researchgate.net/...
1 vote
1 answer
172 views

Hydrophone/geophone sensor sensitivity - noise versus signal

Today, a student asked this question, and I was unable to answer it in a way that was understandable and accurate - even for myself. For seismic data acquisition projects, how are sensors able to '...
3 votes
1 answer
112 views

Wave train 200 m/s meaning

I ran a 60 m line intended for surficial seismic refraction. Energization with hammer. 12 (10 hz vertical 5 m spaced) geophones and 5 shots (15 m spaced). Record length 0.5 s. Thanks to a borehole ...
7 votes
1 answer
1k views

Analytical solution for seismic wavefield in MATLAB

I have been trying to evaluate the analytical solution for a wave travelling in a homogeneous, infinite media. For a given source $S(t)$, the wave-field can be calculated at a distance $r$, for a ...
1 vote
0 answers
162 views

Finding out actual dip and dip direction of refractor

We have two traveltive curves for first arrivals (direct and refracted) from a dipping refractor in the forward and reverse directions along a profile line. my question is: Is there a logical way (non-...
0 votes
0 answers
67 views

Theorist speculate about dozens of loud atmospheric booms across globe

Theorist speculate on the dozens of loud atmospheric booms across globe. Has any recognized institutions offered a plausible explanation as of now?
4 votes
0 answers
49 views

Seismic velocity inversion & analysis

I attended at talk recently at the TGS office in Houston, TX, by Marianna Raunch. During this talk, a statement was made that for "very large" velocity inversions, semblance (or other similar ...
2 votes
1 answer
50 views

Seismic amplitude distribution

Recorded (or raw) and processed pre/post-stack seismic data (relative amplitudes) usually display a standard normal distribution, albeit with a very small amount of skewness. What would be possible ...
1 vote
1 answer
39 views

Seismic wavefield theory: velocity anisotropy

Does the reciprocity principle hold true in an anisotropic subsurface environment?
2 votes
1 answer
102 views

What is the vertical axis of this waveform shown in this tweeted IRIS GIF?

This IRIS tweet shows a video of siesmic waves from the recent M6.4 Earthquake in California rolling across the US. I've made a small GIF to give the idea but the "GIF" in the tweet shows the whole ...
1 vote
1 answer
236 views

How to read Seismic Survey?

Recently I am tasked to create a POC on detection of patterns using a neural . But I am from a computer science background so I know about neural networks but I don't have any knowledge about geology ...
1 vote
1 answer
228 views

wave speed is smaller than both horizontal wave speed and vertical wave speed?

I am new to GIS and just get the idea of slowness. I can understand why people need the slowness in GIS rather than just the reciprocal of velocity. However, I feel the definition of slowness is weird ...
1 vote
1 answer
107 views

Near-Surface Investigations: FWI vs. MASW

MASW is a common processing method for civil/geotechnical and even for oil/gas exploration (usually weathering static corrections) applications. In my experience, it seems to work well for most ...
1 vote
1 answer
155 views

reverse time migration for wave equation PDE using SBP-SAT

I'm stuck implementing a reverse time migration technique, the PDE(partial differential equation) being implemented is an acoustic wave equation, The numerical method being used is a FD(finite ...