28 votes
Accepted

Why aren't seismic stations installed very deep underground so as to pre-warn from earthquakes?

The simple answer is that you can't drill to 50 km depth. The deepest holes ever drilled were to a little more than 12 km, one is named the Kola Superdeep Borehole in Russia, which was a scientific ...
Gimelist's user avatar
  • 23.1k
26 votes

Why aren't seismic stations installed very deep underground so as to pre-warn from earthquakes?

10 seconds is a worthwhile warning time. The Japanese use it to switch off compressors on gas lines (or open release valves on them), emergency break bullet trains, and in particular shut down nuclear ...
Wolfgang Bangerth's user avatar
13 votes
Accepted

How is known that the Earth core is solid?

This is a good observation. The reason we can measure S-wave (transverse) propagation in the inner core is because P-waves can set up S-waves and vice versa. When an S-wave hits the mantle-outer core ...
bon's user avatar
  • 2,221
12 votes

Carbonate reef not horizontal in seismic section?

This phenomenom is called velocity pull-up. The seismic waves that reflected off the top of Layer 2 beneath the carbonate layer have also travelled through the carbonate. Because carbonate (at least ...
stevej's user avatar
  • 1,044
9 votes

Regarding velocity of P/S-waves

That is not a silly question! And your intuition is correct: As you bury and compact a sedimentary rock, its porosity will decrease, so its density increases. But we also see that its velocity tends ...
Antonio's user avatar
  • 947
8 votes

Why aren't seismic stations installed very deep underground so as to pre-warn from earthquakes?

I can see two major benefits of having a 10 second warning time: shutting down gas lines to prevent uncontrollable ruptures and fires after the tremor when comms channels are either destroyed or ...
Deer Hunter's user avatar
  • 2,093
8 votes

Are volcanoes formed from earthquakes?

From what you wrote, you are assuming several things: The mantle is made up of molten rock, Faults can go deep enough to reach the mantle. Both are not exactly accurate. lava starts flowing out ...
Gimelist's user avatar
  • 23.1k
8 votes

Earthquakes in Oklahoma influenced by Humans?

The sudden and recent occurrence of multiple earthquakes in Oklahoma is due to a widespread redistribution of stresses within the ground, particularly at depth. Installing large pipes underground for ...
Fred's user avatar
  • 24.7k
8 votes
Accepted

SEGD and SEGY recorded data

SEG-D is a specialized format, while SEG-Y is a general-purpose format. In general, SEG-D is intended for field recordings of seismic data, and SEG-Y is intended for 'seismic data exchange'. Having ...
Matt Hall's user avatar
  • 11k
8 votes
Accepted

2018 Swan Islands earthquake tsunami

This is the centroid moment tensor published by the USGS as of 01/10/18 (it will likely be updated in the future). As you can see this was an almost pure strike-slip mechanism on a near vertical plane....
bon's user avatar
  • 2,221
7 votes
Accepted

Is it possible to prevent high magnitude earthquakes by induced earthquakes?

The idea of trying to limit energy released by earthquakes and the damage that may result via the use of controlled smaller blast induced quakes is an interesting idea. One of the problems with this ...
Fred's user avatar
  • 24.7k
7 votes
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Using accelerometer as a seismograph

The magnitude of an earthquake is related to the total energy released, therefore to estimate it from a seismogram you need to know the distance to the source. In the case of the Richter scale for ...
Camilo Rada's user avatar
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7 votes
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What is the relationship between raw seismic data, CMP Stacking, NMO & Machine Learning

SEG-Y files are a general purpose archival format. So they can be "anything". 2D seismic, 3D seismic, raw, processed, unstacked or even derivatives (seismic attributes). How to get information about ...
Way of the Geophysicist's user avatar
7 votes
Accepted

Do planetary alignments affect Earth's seismic activity?

It's easy to make prediction of earthquakes in Turkey/Türkiye, it's in one of the most active seismic zones on the planet. The February 2023 earthquake had a magnitude of 7.8, with aftershocks of ...
Fred's user avatar
  • 24.7k
6 votes
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How to interpret seismic interferometry data?

It is a differential InSAR image that shows wrapped phase in radians which is a measure of the change in range (or distance) between the ground surface and a (more or less) fixed point in space from ...
stali's user avatar
  • 2,381
6 votes
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What is the purpose of wavelet extraction from the seismic trace?

We're usually not interested in the wavelet per se, but we need to know it in order to understand how the seismic trace relates to geological properties we are interested in. According to the so-...
Matt Hall's user avatar
  • 11k
6 votes
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Are seismometers over the world "feeling" the small earthquakes caused by air raids and shelling on Gaza Strip?

Bomb explosions are detectable as seismic events, but the energy falls off with distance, so for quakes of less than magnitude 3 you'd have to be with a few 10s of kilometers, depending on your ...
jeffronicus's user avatar
  • 3,523
5 votes

Earthquakes in Oklahoma influenced by Humans?

Short answer is that no this is not normal, which is why there are experts descending on the area to study the situation. Your first theory is not likely to be an issue, as oil is produced from a ...
blaydes's user avatar
  • 121
5 votes

Relationship between tides and earthquakes

I don't find Ide et al's recent paper to be very convincing. They only studied three earthquakes - hardly a statistically representative sample. There are millions of earthquakes on record, and ...
Gordon Stanger's user avatar
5 votes
Accepted

Prompt gravity signal induced by the 2011 Tohoku-Oki earthquake - could this really be useful for warnings?

If you have a sufficient number of sensors, e.g., land-based or ocean-bottom seismometers, in the vicinity of where strong earthquakes typically happen, then it will take a few seconds for seismic ...
Wolfgang Bangerth's user avatar
5 votes

What causes ringing effect when using corner filter?

Filtering is always a convolution of the signal. What you are doing in the frequency domain will also be manifested in the time domain. A sharp edge in frequency domain will create a long convolution ...
user2821's user avatar
  • 5,946
4 votes

Good Open source alternatives to SeisImager & RES2DINV?

Actually, there are plenty of alternative DC Inversion software; I hate using res2dinv; unfortunately it's relatively easy to get into. I would have much preferred ZondRes2D for it's user experience. ...
Coastal's user avatar
  • 146
4 votes

How can we determine the size and composition of Earth's inner core?

In 1906, Richard D. Oldham found that the increasing speed of seismic waves with depth within the Earth holds only down to 2890 km below the surface. Deeper than that, the mechanical waves (sound) ...
DrGC's user avatar
  • 1,753
4 votes
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How do they know the 2016 Kaikoura (NZ) Earthquake was 'complex', involved six different faults?

You need to see the InSAR data. E.g., see this image which is based on radar data acquired by ESA's Sentinel-1A satellite. For straight faults the pattern is not this complicated. Using such ...
stali's user avatar
  • 2,381
4 votes

Is the centre of Italy still at risk of earthquakes?

The Italian Civil Defense's map of earthquake risk zones shows Rieti in at best Zone 2, "Medium-high seismicity, quite strong earthquakes possible", and near or in Zone 1, "High or catastrophic ...
cphlewis's user avatar
  • 531
4 votes
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Which type of seismic sensors usually used in Earthquake Early Warning?

Accelerometers, preferably triaxial (i.e., those that record horizontal and vertical motion). Beyond that your question is indeed a bit too open-ended. Some use many cheap MEMS (http://onlinelibrary....
Erik's user avatar
  • 1,999
4 votes
Accepted

Would climate change result in an increase in seismic activities?

Dilation of the Earth's surface due to atmospheric temperature changes will be negligible due to the amount of temperature increase. Stronger precipitation will not directly lead to an increase in ...
Fred's user avatar
  • 24.7k
4 votes

Does the Moon affect earthquakes?

Actually, yes, but indirectly Well, the tidal forces produced by the Moon's gravity are not enough to distort the Earth's crust enough to produce any significant displacements of the crust, and ...
Alastor's user avatar
  • 261
3 votes

Global scale seismology experiments / observations disproving flat earth conspiracy?

As you rightly say, seismicity is one geological proof of an almost spherical planet, but surely it is far easier to prove your case by satellite data, such as scenes from http://weather.msfc.nasa.gov/...
Gordon Stanger's user avatar

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