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
64 views

gamma-ray spectrum vs energy decay

I am going through An Introduction to Applied and Environmental Geophysics, a book by John Reynolds (2011), to better understand radiometrics and gamma-ray spectrometry. The author provides some ...
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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 on a ...
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Why do we consider hydrostatic pressure and lithostatic pressure separately?

In petroleum geology, why do we consider hydrostatic pressure and lithostatic pressure separately? Surely the pressure at any point, whether fluid or rock, at depth is simply equal the weight of all ...
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Simple way to understand these narrow frequency peaks in recently published “ice shelf singing”?

The Earther.Gizmodo.com article Scientists Discover a Weird Noise Coming From Antarctic Ice Shelf links to the American Geophysical Union video (an more importantly audio) (AGU) This is what an ...
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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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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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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 ...
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1answer
215 views

If all the world's ice were to melt, would this shift the earth's centre of gravity with consequential effects on sea levels?

This question on Maths SE asked how we might calculate the effect on sea level if all the world's ice (ie including the whole Antarctic ice sheet) were to melt. I posted an answer containing ...
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Is there a “submerged object” in Australia that causes a magnetic deviation of 20 degrees?

This answer quotes this blogpost as an example of a magnetic anomaly: Basalt formation, “Mt. Jim”, in remote north-east Victoria, Australia, has a magnetic anomaly -20 degree magnetic compass ...
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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 ...
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421 views

How do the different densities of the oceanic and continental crust affect earth's outer shape?

I am currently reading a textbook and I am slightly confused at a paragraph that deals with some general facts about earth's outer shape. It mentions that the density of the continental crust is ...
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1answer
90 views

Where on Earth is the highest none polar magnetic fields?

Is there anywhere that magnetic ore deposits are strong enough to have a magnetic field that would be stronger then Earths' magnetic poles by proximity? I'm not asking Where on Earth is the ...
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Does the global temperature vary daily (hotter and colder days)?

Earth's current average global temperature (i.e. including hot deserts and cold polar caps) is reported be somewhere between 14°C and 16°C (depending on sources and methods). This temperature varies ...
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Seeming correlation between time of day and earthquakes

I live in a generally geographically active area (Southern California, near the San Andreas fault, if that matters), that has had two relatively minor earthquakes that I have felt in the last week (in ...
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Why are pole reversals not more detrimental to life?

This question is linked to the following question, and has two parts. Mars interdicts approximately 40% of the radiation (per square meter) of the sun that Earth does. It has been claimed that Mars ...
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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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3answers
380 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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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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25 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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1answer
73 views

What voltage and/or amps cannot be found naturally?

Electricity can come in many forms on Earth but when is amps and/or voltage limited physically on Earth? In other words, what voltage arises naturally on Earth?
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What physical measurement / elevation is used to define Earth's radius?

Earth's radius is usually given as 6378137 meters (equatorial radius), its flattening is defined as 1/298.257223 (WGS84), and thus its polar radius is calculated as 6356752 meters. However, the ...
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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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1answer
74 views

What theories exist connecting volcano temperatures to eruption probabilities?

Wikipedia names thermal monitoring as one of the methods for predicting volcanic eruptions. I was able to find some papers (First, Second) on such thermometry and while they are challenging (I retired ...
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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?
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148 views

Where on Earth is the most windless lake with its own micro climate sea breeze?

Would a circular lake have enough of sea breeze strong to create a gentle vortex in the center of the lake? Is there such a place on Earth where lake micro climate vortexes occur frequently? The ...
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308 views

Is an underground mine collapse or a tunnel collapse called a sinkhole?

Imagine there's an underground man made structure e.g. a tunnel or an underground train station that collapses creating a depression in the surface. Would that technically be called a sinkhole? What ...
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2answers
548 views

Why doesn't subducted earth crust melt?

If you take a look at a typical picture tectonic plate subducting under another plate, the subducting plate is always drawn as deep (seemingly tens of km) into molten rock, but the subducted part of ...
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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 ...
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1answer
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Plate boundary lon/lat data

I'm working on a map in GMT and am having trouble finding lon/lat data for the minor plate boundaries (specifically the adriatic). Is there a database I can refer to?
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351 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 ...
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1answer
667 views

What exactly are enantiotropic and monotropic polymorphic transitions?

Recently, I've been studying the subject of polymorphism and met two important concepts, the monotropic and enantiotropic polymorphic transition types. However, I can't really seem to grasp the ...
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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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1answer
294 views

Temperature differences in sand

Sand is granular in nature, which allows air columns to trap in between them. As we know that air is an insulator of heat. So here are my questions: Does sand maintain its temperatures close to its ...
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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
89 views

Why do clouds have ceilings and bases?

What is the point called when water can not rise above or visually seem to have a ceiling in the atmosphere? What makes that point ideal?
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1answer
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Does the extension of the absorption line of $\text{CO}_2$ with temperature play a role in the climate change?

I've read not long ago that the absorption line of the $\text{CO}_2$ becomes larger with temperature thanks to Doppler effect (if it's false it would be great to tell me). My question is the following:...
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Does the Earth 'Flare' like the Sun does?

Solar Flares are a commonly discussed phenomenon, which have effects ranging from geomagnetic storms to radio disruptions to absolutely nothing noticeable. Given that part of the core of the Earth ...
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3answers
110 views

Need seismic data and digital well log data from the same area?

I am currently working on a project that involves the input of seismic attributes (instantaneous amplitude, instantaneous frequency etc.) to a machine learning/deep learning model (eg. A Neural ...
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1answer
45 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 ...
3
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1answer
238 views

Open source well information viewer

I am in the middle of a hobbyist experiment and would like suggestions on an open source HTML viewer for mud loggging, FMIs, lithology and seismic. I have used INT before but for this project I would ...
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1answer
157 views

Difference between model parameter and observable parameter

In Inverse problem theory, what is meant by "results of the measurements of observable parameter"?
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47 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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2answers
157 views

Winter in the Northern Hemisphere in July? Can anyone explain it?

The July 2007 issue of the National Geographic Magazine dedicates several pages to "Climate Change" and "Global Warming". The author explains in detail the Earth's movements and how they provoke ...
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Utah rock pattern identification - looks like small craters

This formation was found in the Capital Reef area of Southern Utah (38.2970546, -111.2979319). There wasn't just one, but several of these small crater formations all over the area. All of them had ...
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Where on Earth is the magnetic field intensity stronger?

Are there places on Earth that have a strong magnetic field other than the magnetic north and south poles? Can living where (rare) earth magnetic ore is abundant provide a mini-magnetoshere?
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1answer
230 views

Seismic migration concepts

In Dr Hua-Wei Zhou's book Practical Seismic Data Analysis (2014), he includes and explains figures from previous classic works (i.e. Schneider, 1971) in order to describe migration from a fundamental ...
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371 views

Is altitude of everything decreasing due to sea level rise?

We know that sea level is rising, though some people say climate change is fake. Altitude is defined as the height of something measured from sea level. Since sea level is increasing, and the ...
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Does anyone have absorption coefficients at different wavelengths for sulfur dioxide? [closed]

Does anyone have absorption coefficients for sulfur dioxide at various wavelengths?
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883 views

What is the difference between radiation balance and the global energy balance?

Looking at two diagrams below, they seem to depict the same system. How are they different? Why one is a radiation balance model and the other a global energy balance model? RADIATION BALANCE MODEL: ...
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2k views

Changes in Earth's orbital and rotation speeds

What are the Earth's maximum and minimum orbital speeds around the Sun? Is there any way to calculate orbital speed at any point of Earth's orbit? Is there a way to relate this to the calendar? Does ...