31 Answered Questions for the topic Geophysics

07/24/19

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... more
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07/22/19

Do our continents lay on the mantle because solid silicon dioxide is less dense than its liquid form?
I don't know whether quartz behaves like ice or not, but could it be because silicon dioxide, which the continents are made of for a big part, is less dense - so the continents lay on top like ice... more
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07/11/19

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... more
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07/04/19

Why do we measure eustatic sea-level from the center of earth?
Earth is rotating so it has a ellipsoidal shape. The measurement will therefore be different from equator and pole. So why do we measure eustatic sea-level from the center of earth?
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07/03/19

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... more
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07/03/19

What is the difference between a geologist and a geophysicist?
What are the main differences between geologists and geophysicists?
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06/25/19

What would change if our earth lacks mountains?
I just asked myself what is the role of the mountains on our planet earth? Well there's a well known role for the climate and weather. But is there a kind of physical or geological role? What... more
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06/25/19

What is the current status of geophysical global cooling theory?
Plate tectonics effectively rubbished the theory of geophysical global cooling as a means of explaining many surface features on the Earth. However, [this... more
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06/25/19

What are the challenges in predicting lithology directly from acoustic impedance?
Seismic inversion methods help to visualize the subsurface layers of the earth in terms of petrophysical properties (e.g. impedance). Still some geophysicists use the final inverted impedance model... more
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06/17/19

Why are minerals found in "large" quantities and not scattered throughout the earth as individual atoms?
Heavier elements are created in stars. After stars die they scatter these heavier elements throughout the universe. These elements eventually gather to form planets. But why do we find "chunks"... more
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Geophysics Geology

06/15/19

How is the mass of the Earth determined?
According to textbook knowledge, the mass of the Earth is about 242kg. How is this number determined when one cannot just weight the Earth using regular scales?
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06/10/19

What is the current status of geophysical global cooling theory?
Plate tectonics effectively rubbished the theory of geophysical global cooling as a means of explaining many surface features on the Earth. However, [this... more
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05/28/19

What do the derivative or the integral of amplitude of a seismogram mean?
I'm doing a project in which I'm analyzing earthquake seismogram waves. I used a program to graph the exact amplitudes and how they changed over the course of a single earthquake. For the project I... more
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05/22/19

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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05/21/19

What would change if our earth lacks mountains?
I just asked myself what is the role of the mountains on our planet earth? Well there's a well known role for the climate and weather.But is there a kind of physical or geological role? What would... more
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05/18/19

How do seismologists locate the epicenter and focus of an earthquake?
I know the focus of an earthquake is where the earthquake originated from, but what I could never figure out is, how to scientists find out where exactly the focus (and epicenter) are located?
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05/12/19

Could evidence of a signal from an exocivilization be found in the geologic record?
We know that the current SETI efforts have not found evidence for the existence of intelligent exo-civilizations (XCIV). There also has not been any evidence found of ancient non-human... more
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05/10/19

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?... more
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05/09/19

Are there water molecules in the oceans which will almost never fall down as rain?
Some oceans are very deep. But is there also current (convection) deep in the ocean so that all water molecules will ones be evaporated and fall down as rain or is it very quite at the bottom so... more
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Geophysics Geology Time Earthquakes

05/09/19

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... more
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05/06/19

Can rocks have pressure signatures?
Since rocks can have magnetic signatures, as is the case with paleomagnetism, can they store past pressures also? For example, when researchers are trying to determine past ocean levels, they... more
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04/20/19

Why are minerals found in "large" quantities and not scattered throughout the earth as individual atoms?
Heavier elements are created in stars. After stars die they scatter these heavier elements throughout the universe. These elements eventually gather to form planets. But why do we find "chunks" of... more
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Expert Answers •1

04/20/19

Can rocks have pressure signatures?
Since rocks can have magnetic signatures, as is the case with paleomagnetism, can they store past pressures also? For example, when researchers are trying to determine past ocean levels, they... more
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04/12/19

Does gravity differ from place to place on Earth?
Does a particular object have the same weight on every part of Earth or does it vary?
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04/11/19

What do the derivative or the integral of amplitude of a seismogram mean?
I'm doing a project in which I'm analyzing earthquake seismogram waves. I used a program to graph the exact amplitudes and how they changed over the course of a single earthquake. For the project I... more
Follows • 1
Expert Answers •1

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