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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1answer
230 views

Calculating error in measuring geomagnetic Anomalies using IGRF

In textbooks it is mentioned that Magnetic anomaly = Observed Geomagnetic field - Theoretical Geomagnetic field observed value is measured using instruments like proton precession magnetometer or ...
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1answer
132 views

What current evidence is there for a Glacial Hudson River Valley deluge?

Some have studied the Lake Missoula glacial dam breaking West and having created the Coulees of Eastern Washington. Who's studied the glacial dam breaking South and having cleared the Hudson River ...
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1answer
959 views

Why is phase rotation needed to produce the colored inversion operator?

In seismic analysis, why is a –90 degree phase rotation required on the amplitude spectrum to produce the colored inversion operator?
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50 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 ...
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2answers
100 views

Can an igneous rock have a Vp of less than 1000 m/s and need blasting to excavate?

I have run a 60 m refraction seismic line on a mountain summit. The environment was noisy (wind would be the principal agent) and quite difficult to pick first arrivals. It resulted in 800 m/s. A ...
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0answers
14 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 ...
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57 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 ...
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0answers
95 views

Free geophysical software with GUI [closed]

I'm looking for free software for marine surveying, such as Madagascar and Seismic Unix, but preferably with a graphical user interface
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0answers
155 views

Why are all rainbows are not the same? [closed]

How does these rainbows water drops differ? I know it has to do with the size of water drops refracting light. Is there a formula that determines the type of rainbow? Icebow Unlike this questions ...
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226 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 ...
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0answers
271 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 ...
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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 ...
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0answers
93 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 ...
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2answers
123 views

Centripetal Force Perfect Ball and Water

I made a question in WolrdBuilding as I was directed to. There a user said that with a perfect ball all water would pool to the equator because of centripetal force. What I do not understand is how ...
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1answer
101 views

What kind of purple stone is this? [closed]

I found this stone and I do not know what type of stone is this?
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1answer
199 views

Hydrology- flow accumulation

I'm not specialist in hydrology, and I would be very grateful if you answer my question: What is flow accumulation in hydrology? Why algorithms used to calculate it over a raster DEM don't take ...
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2answers
99 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. ...
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1answer
326 views

Is heavier bodies fall faster than lighter ones [closed]

Suppose we have two stones, the first being lighter than the second. Release the two stones from a height to fall to Earth. Stone 2, being heavier than stone 1, falls more rapidly. If they are joined ...
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1answer
90 views

How much would a nine inch slice of the Earth's inner core weigh? [closed]

If one took a slice of the Earth's inner core measuring nine inches across how much would that slice weigh? Or, conversely, how much mass would that contain?
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1answer
4k 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 ...
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1answer
291 views

Quality control in Seismic Acquisition - How much data is required?

When it comes to land or marine acquisition (oil exploration, for instance), I can see from literature that quality control (QC) is performed during the survey to ensure that the seismic traces ...
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2answers
382 views

What is the highest balloons possible in a chain?

The BU60-1 balloon attained an altitude of 53.0 km (32.9 mi; 173,900 ft). Weather permitting, would a series of climbable balloons in a chain be able to be linked from the ground to that height of ...
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1answer
172 views

Heat at High Altitudes

Why does the temperature of let’s say 85 degrees Fahrenheit in southern California feel hotter at 7,500 ft elevation than it does at sea level?
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1answer
48 views

Love-Wave Propagation

Love-waves cannot exist in a half-space. Layering must be present and there also must be accompanied impedance contrasts associated with the layering. Because layering naturally induces seismic ...
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1answer
148 views

Volcanic Eruption Calculation?

I was trying to find the amount of energy created during a volcanic explosion, I have been looking around, There was one formula I found where I could use the Kinetic Energy, which is $KE=\frac{1}{2}...
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1answer
34 views

Rainbowish phenomenon outside my home

I took a photo of an amazing sight I had never seen outside my home ( southern india ) but I could not tell if it was a rainbow type thing or an aurora borealis. Also if it was to be a sun dog , ...
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1answer
78 views

Barotropic vorticity equation

I came across the barotropic vorticity equation (below) in Sakamoto (2002) and I cannot figure it out. The notation is not clear to me. How can it be derived from the Navier-Stokes equation? $$ \beta\...
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1answer
21 views

Does the shear modulus of silicate minerals vary significantly with changes in P and T?

I know that the bulk modulus, K, varies with pressure and temperature for silicate minerals and liquids, but what about the shear modulus? If so, is the change drastic for changes from standard ...
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3answers
463 views

Volcanic eruption force

From my research, some volcanic eruptions can produce enough force to turn a 10-tonne rock into a projectile. Could a supervolcano produce enough force to turn a 35,000 tonne rock into a projectile? ...
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1answer
834 views

What equation should I use in this isostasy problem?

I have this problem, and I am not sure where to start. The only Airy equation in my text is $r_1= \frac{h_1 \cdot p_u}{p_s - p_u}$. This doesn't seem to apply, or if it does it isn't obvious. Is ...
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1answer
104 views

What is seismic stretch in geophysical method?

What is seismic stretch in geophysical method ?
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1answer
68 views

Forest rings shape regularity

In the answer to "Why is ground water rising on these forest rings?" it is written: these rings are too numerous and too regular in shape to be related to either kimberlites or (even more ...
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0answers
31 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 ...
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0answers
59 views

How does the changing seasons affect the large scale easterly flow of the ITCZ?

I am new to climate science and have been learning the basic picture of the intertropical convergence zone (ITCZ) and how this leads to the predominant easterly "trade winds". The picture that I ...
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32 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.
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0answers
138 views

Equatorial Bulge and its implications on the climate

How much of the variance in the climate is due to the equatorial bulge and how much sun radiation do we lose due to the equatorial bulge? I am interested in the variance both through time and ...
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0answers
39 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-...
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1answer
99 views

Effects of Centrifugal Force on Gravity Vectors?

I've been asked this question twice now from our favourite science denying community, and I don't know how to parse it. I can do centrifugal force and gravity given mass, but have never tried to even ...
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0answers
14 views

Determining the spatial orientation of a fault given ground acceleration magnitude in different directions

Accelerographs measure ground acceleration in three different components of motion: east-west, north-south, and vertically (up-down). I know that fault orientation is important here, so let's say we ...
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0answers
78 views

Which is naturally more radioactive: a tertiary or cretaceous sandstone? Why?

I've come across this question in a Petrophysics exercise regarding the Gamma Ray well logging. And I don't know how to solve it. This is the "believed" AFAIK session Natural radioactivity ...
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1answer
104 views

Is this a rock with metal or gold? [closed]

I found these really hard rock while i was excavating. It caught my attention the different colors.
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0answers
28 views

Which wavelengths is limestone most transparent to?

I think of the non-ionizing range, e.g. Terahertz or Radio. Limestone clearly is transparent to x-ray or gamma but thats not what i am asking for. Natural to low ranges of porosity/water content ...
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0answers
20 views

Do living things have a magnetic field capable of any level of solar protection?

I understand how anything with an electrical current have a magnetic field including living things. Would a densely populated rain forest or jungle have enough combined magnetic field among the living ...
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0answers
26 views

Is there a formally-defined converse of a Prominence Walk?

My question was inspired by this one - in particular, the subtopic of pumping water from the ocean to the below-sea-level basins to deal with rising sea levels (spoiler: it's horribly infeasible and ...
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0answers
62 views

Easiest way to find the water table under my feet

I had burnt my finger by digging an empty well and spending my hard-earned money in vain. I then started to study about the resistivity method for finding underground details. But I have many doubts ...
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0answers
89 views

Why does the lithosphere thickness vary within a short distance?

Can someone explain why the lithosphere thickness varies within a short distance (30-100km) at the same upper mantle viscosity around the polar region? And what is the behaviour of a thin (20-70km) ...
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1answer
47 views

Is there any rule of thumb to decide the indentation hardness test?

How to decide whether Brinell Hardness test, Rockwell test or Vicker's test is to be applied as far as grain-size is concerned? Is there any rule of thumb to decide the type of indentation hardness ...
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0answers
50 views

Interpretation of horizon display

I am currently working on a project that involves using seismic attributes as input parameters in a neural network for estimation of porosity and permeability for a reservoir. Now, I need to correlate ...
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0answers
75 views

How can this fountain of (hot?) water coming out of the Earth arise?

In this video from min. 7:00 is after digging in the Earth a fountain created of water. Is this due to the pressure of the water in the Earth, if so how did it get there and how did it get such a high ...
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55 views

Why is the Inner Core of the Earth solid in spite of being the deepest and the hottest layer of the Earth [duplicate]

I have been recently studying about the layers of the earth and I got stuck with the question that why is the inner core of the Earth solid in spite of being the deepest and the hottest layer. I hope ...

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