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
347 views

Can a shock wave travel around the Earth's curvature?

Can an explosion be felt in the ground on the opposite side of the Earth like from an asteroid? Would planes in the air on that side of the Earth be able to survive? Does the shock waive follow the ...
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1answer
4k views

How did the Ural mountains form?

A nice picture for "how mountains formed" on Earth is due to the motion of tectonic plates. As the plates crash together, mountains may get "pushed upwards". However, a quick look at a map of the ...
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Safest spots when an asteroid hits? [closed]

I am breaking this question and no longer making an effort in refining it with the exception of adding an associated link with the scenarios. I always wondered if a devastating asteroid was ...
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2answers
322 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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2answers
5k views

Where is the calmest place on Earth?

I have done some research online, and I've found out that Antarctica has the calmest winds (lowest maximum wind speed) recorded on Earth. However, it is uninhabitable for human life. Other very calm ...
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0answers
142 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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0answers
67 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 ...
8
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1answer
311 views

Is the iron on Earth's crust a leftover of the Iron catastrophe, or it was brought back by volcanoes?

When pondering the hypothesis of the Iron catastrophe, that seem to be widely accepted nowadays. It surprises me that currently the crust still contain a significant amount of Iron (5.6% in weight). ...
3
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1answer
439 views

What structures form due to the melting of subducting plates? [closed]

What structures form from the melting of subducting plates? Plutons, Accretionary wedges, Deep sea trenches, Faults?
2
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1answer
935 views

Which type of convergent boundary creates the tallest mountains? [closed]

Which type of convergent boundary creates the tallest mountains? Continental-Continental Ocean-Ocean Ocean-Continental
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1answer
652 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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2answers
152 views

How to graph gravity as a function of depth, given radius and density?

I need to do this for a planet that has uniform density, and a planet that has two layers. For the first part, I was given that the density was 550 kg/m³, so I made one column in an Excel spreadsheet ...
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1answer
352 views

What factors explain mountain glacier retreat variability?

It is well known that the majority of the world's mountain glaciers are retreating, but looking at a few LANDSAT images from the 1980s and today I am able to see glaciers that have retreated ...
4
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1answer
813 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 ...
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1answer
89 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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2answers
615 views

Megathrust earthquakes on subduction zones

I am a beginner in geology and earthquake studies, and learning about subduction zones recently. Question is: do large earthquakes (sometimes referred to as megathrust quakes) occur on any point in ...
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2answers
551 views

Acoustic impedance in geophysical context

What is the intuition behind acoustic impedance? Yes, I know that it is the opposition to a seismic wave travelling in the medium. But why it is defined as density × velocity? The velocity of a ...
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2answers
102 views

Aspiring Geophysicist

I am interested in becoming a geophysicist. I am currently doing my undergraduate degree in the UK but have not chosen a specialisation. Is it better to specialise in Earth Sciences as an undergrad or ...
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0answers
216 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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1answer
78 views

What is seismic stretch in geophysical method?

What is seismic stretch in geophysical method ?
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1answer
66 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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1answer
115 views

Is there a high-temperature, non-magnetic glue that doesn't dissolve in water?

I have very small mineral samples, and I'm looking for a glue that can hold them through a sample preparation process that I'm doing: heating, polishing, and measuring magnetic moment. For that I want ...
3
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1answer
538 views

Rossby radius as horizontal scale

In the introduction of "Geographical and monthly variability of the first baroclinic Rossby radius of deformation in the South China Sea", the authors states: In both theoretical and observational ...
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73 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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1answer
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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?
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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 ...
5
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1answer
191 views

How can I calculate the sensitivity of a seismometer?

I would like to know if a specific seismometer can measure 1 micron/sec velocity. I have a few specs from the datasheet but I'm not a seismologist and am trying to figure out how to relate the specs ...
2
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1answer
217 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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4answers
485 views

In the oil field, when a vertical cylinder coring sample is taken, how is the core severed at the bottom and removed from the formation?

I would like to know how the core is cut off at the bottom of the drill. I also would like to know how the core is brought up to the surface without slipping out and falling back down.
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1answer
175 views

What is trace-based seismic Inversion

Looking through different literature articles and books concerning seismic inversion - mostly post-stack - phrases like "trace-based" and "model-based" keep appearing. I know that model-based in when ...
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1answer
357 views

What causes ringing effect when using corner filter?

I used the corner filter (band pass) with this frequency values (8,10,45,50). I get ringing effect on the data. my questions are: what is the name of this effect and the cause? should be removed and ...
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1answer
381 views

How to calculate cumulative moment magnitude?

What is the proper way to calculate cumuluative moment magnitude if I know the moment magnitude of several earthquakes?
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1answer
2k views

Why is the temperature between the earth core and surface not distributed linearly?

So I read somewhere that the inner core temperature of Earth might be as high as 7000 °C. Depending on the composition of the different layers towards the surface, the temperature should decline ...
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0answers
236 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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2answers
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Is winter hotter at the Equator?

I live in the Northern Emisphere. One of the things I have been taught when I was in high school is that winter is colder than summer because in that season we're at an unfavorable angle and nights ...
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1answer
550 views

What's up with the “jelly sandwich” analogy of the lithosphere, asthenosphere and mesosphere?

Here's what I know: The lithosphere is hard because it is cold and low-pressure. The asthenosphere is more deformable because of higher temperatures and pressures. The mesosphere is below the ...
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2answers
2k views

How do seismic charges help to investigate the subsurface?

In the film Kong: Skull Island, scientists investigate an island's structure by dropping explosive charges from helicopters: Source: YouTube trailer In reality, geophysicists do something similar ...
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2answers
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Is there any case that changed from earthquake safe zone to danger zone?

Is there any case that changed from earthquake safe zone to danger zone? As plates move, I think that earthquakes belt will change over time. But is there really a case in which the earthquake-safe ...
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1answer
140 views

Cooling time of basalt flows?

In places like the Giant's causeway in Ireland (Antrim basalts) there are columnar basalt flows of 100 metres or more. I'm aware that the cooling mechanism is complex, but is there any rough and ready ...
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2answers
315 views

Is the Earth heated up by the tides?

Reading about moons of other planets they often get heated up by the tides so for example Io and Europe of Jupiter get friction by which eruptions and liquid water can arise. But is there also an ...
7
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1answer
412 views

What “g” would be needed to keep helium on Earth?

I know that helium is a very light and rare gas on Earth because Earths gravity is not strong enough to keep it. Instead, helium and hydrogen are rising through the atmosphere and escape into outer ...
2
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1answer
118 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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Are there any signs on the Earth's surface that indicate a shrinking iron core? [duplicate]

It appears that Mercury shows some cracks on its surface that were not caused by moving tectonic plates but by shrinking due to the inner metal core cooling. The Earth is also cooling down, but are ...
4
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1answer
237 views

Surface temperature in early hadean period

I am considering earth's internal heat budget for a project in university. For this I need an estimate on the temperature of the earth shortly after it had formed. In Kelvin's On the Secular cooling ...
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2answers
130 views

Why do buoyantly rising mantle minerals melt, yet buoyantly rising atmospheric waters condense?

In the mantle, minerals contained in buoyant plumes of rock undergo phase changes from solid to liquid (decompression melting). In the atmosphere, waters contained in buoyant plumes of air undergo ...
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1answer
987 views

How much water is the atmosphere losing to space?

Up until recently, I was under a (wrong) impression that the amount of planetary cumulative water resources was finite as I believed its escape from the atmosphere was impossible. I believed that, ...
10
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1answer
95 views

Does the Earth receive a net charge from the aurorae?

The sun radiates a lot of charged particles to the Earth. When the magnetic field of the Earth lines up to the poles, we get the beautiful polar lights. But are there as many negative charged as ...
3
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1answer
79 views

How much of the Earth's heat is caused by the hot centre?

What is the percentage of the Earth's warmth that the Earth's hot centre is responsible for? What would be the temperature of the atmosphere if the Earth's centre was 18° C (average temperature on the ...
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1answer
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Is “seismic energy released” a regionalized variable and can be analyzed using geostatistics?

In geostatistics, we can assess and analyze regionalized variables. Tectonic stresses releases in seismically active regions by occurring earthquakes. We can calculate and estimate the seismic energy ...
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430 views

Are old geophysics textbooks useful?

I have had much success with old textbooks in mathematics. Generally, for any branch of mathematics that I (as a non-mathematician) would like to learn or re-learn, I can buy a classic textbook from ...