Questions tagged [seismology]

For questions about the study of earthquakes and various seismic sources.

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2
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1answer
419 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?
7
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1answer
314 views

How to interpret seismic interferometry data?

Here is a screenshot of coseismic interferometry measurements of the 2015 Nepal earthquake. What does it mean? The star is the epicenter of the earthquake. The screenshot was taken from the UNOSAT ...
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0answers
69 views

Comparing the 4th of August 1998 earthquake to the 16th of April 2016 earthquake in Ecuador

I'm doing an assignment where I'm comparing the two mentioned earthquakes, and trying to figure out which factors played a role in the amount of casualties. In the 1998 earthquake there were only ...
4
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1answer
237 views

What (if anything) can be learned from accurately recording tilt motion during seismic events?

The Rotational Motions in Seismology (ROMY) instrument is a giant laser gyroscope used to generate extremely precise 3D rotation measurements of planet Earth. However at the end of the video below ...
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0answers
121 views

Earth's inner core has an inner core inside itself. Are there three inner cores?

The Seeker.com article Earth's Inner Core Has Its Own Inner Core states that researchers at University of Illinois and Nanjing University in China have made a bizarre discovery. They've found that ...
6
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1answer
740 views

seismic wave detection standing at the epicenter

If a person is to stand at the epicenter of an earthquake. Is it true that he would not detect P-waves nor S-waves echoing off the mantle core boundary? Since if P-wave that enter perpendicularly ...
6
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2answers
3k 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 ...
13
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1answer
3k views

Using accelerometer as a seismograph

I'm using ADXL345 accelerometer with Raspberry Pi to build a seismograph. I've successfully hooked it up and can plot the accelerometer data in three axis. Is there any way to express these data in ...
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1answer
1k views

Can large earthquakes happen few times at same place(in days)

I want to know if large earthquakes can happen twice in the same place? I live in Istanbul/Turkey. In Canakkale/Turkey too many earthquakes happen for days! I know it is normal for this region but 4.8 ...
7
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1answer
666 views

Analytical solution for seismic wavefield in MATLAB

I have been trying to evaluate the analytical solution for a wave travelling in a homogeneous, infinite media. For a given source $S(t)$, the wave-field can be calculated at a distance $r$, for a ...
6
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1answer
689 views

How does moveout correction work in seismic reflection profiling?

When you take a seismic reflection profile you take multiple shots and then stack them together around a common midpoint. Due to the extra distance travelled by the wide angle shots there is a moveout ...
5
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1answer
68 views

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 ...
8
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1answer
213 views

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

Edit: Two new items may shed more light on this question: BBC: Gravity signals rapidly show true size of giant quakes links to: Science: Observations and modeling of the elastogravity signals ...
7
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2answers
173 views

How do they know the 2016 Kaikoura (NZ) Earthquake was 'complex', involved six different faults?

The BBC news article New Zealand quake: The geological impact of a 'complex' tremor says: The powerful earthquakes which hit New Zealand were some of the most complex ever recorded, say scientists. ...
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0answers
139 views

How to find instrumental response for a seismic station

I received seismic data for which I would like to remove the instrumental response. The only information I have is that they were recorded on a Trillium broadband seismometer with a cutoff period of ...
4
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1answer
142 views

Relationship between tides and earthquakes

Ide et al. (2016) suggest that earthquakes (especially those of high magnitudes) are more probable during periods of high tidal stress (during full and new moons). While they show a comprehensive ...
5
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1answer
84 views

Is the concept of seismogenic zone still relevant after the 2011 Japan earthquake?

The concept of subduction seismogenic zone, where megathrust seisms occur in a layer between an upper and a lower limit is well documented in the 1990/early 2000 literature : Some example : Pacheco,...
2
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1answer
354 views

Fault representation

In most illustrations and diagrams of the types of faults, there is always something similar. I noticed that there is a side of the hanging wall and foot wall which is slanted. We're supposed to make ...
2
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1answer
172 views

Are the other causes of an earthquake (e.g. volcanic eruptions) the cause of the “sudden slip” which is the main cause of an earthquake?

I am to deliver an informative speech about earthquakes in class. However, I was not the first to talk about earthquakes and his discussion of the cause of earthquakes is different from mine. He ...
3
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1answer
1k views

Detecting seismic waves using Software Defined Radio

I understand about physic and waves, but I am a totally rookie in this topic. I was wondering which are the typical frequency ranges of the S-waves, P-waves and surface waves. My idea would be to ...
2
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1answer
1k views

Seismology: What causes an earthquake? [closed]

I am doing a research on earthquakes but I cannot fully understand what causes earthquakes. "Caused by a sudden releases of energy by the Earth's crust, causing seismic waves which causes the ...
5
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0answers
54 views

Seismic attenuation in mixed gas/water

Imagine I set off an airgun in the ocean and I measure the far-field signature. Then I do the same thing shortly after introducing tiny gas bubbles into the water, and mixing them well. Are there ...
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2answers
302 views

Tasmanian earthquake patterns

While researching across the Australian Earthquake Engineering Society archive about Seismology, I came across an earthquake map of the Australian island state of Tasmania (below): I am aware that ...
5
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1answer
418 views

Global scale seismology experiments / observations disproving flat earth conspiracy?

Recently I've taken an exceptionally unwise interest in the beliefs on conspiracy theorists, in particular flat earthers. Flat earthism has been trending heavily lately and indeed is undergoing some ...
13
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1answer
637 views

How is known that the Earth core is solid?

As I know, the Earth core is solid. This is known, because it conducts also transverse waves, while liquids conduct only longitudinal waves. But, how was it found? The inner core is in the outer core,...
10
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1answer
366 views

Carbonate reef not horizontal in seismic section?

Carbonate reefs usually appear as homogeneous bodies surrounded by sediment layers in seismic reflection data, but in the figure below the high amplitude reflection from the top of sediment (layer 2 ...
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2answers
965 views

Good Open source alternatives to SeisImager & RES2DINV?

Are there any good open source (Linux) alternatives of SeisImager which includes Pickwin and Plotrefa and file formats are .sg2? Same question for ...
3
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1answer
636 views

Seismic data processing software

For processing seismic data, why is Seismic Unix so important? What distinguishes it from other seismic processing software like GLOBE Claritas or Omega? Is it argued that processing capabilities are ...
8
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1answer
140 views

Regarding velocity of P/S-waves

I feel like I am missing something blindingly simple, but I am curious about something. We are given the velocity of a P-wave as $v_{p} = \sqrt{(K+\frac{4}{3}μ)/ρ}$. So I am to understand ...
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0answers
33 views

Earthquake data acquisition Geosig VE-53

Is it possible to receive data from a Geosig VE-53 to a PCI data acquisition (serial port) connected to PC and without using a recorder?
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5answers
4k views

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

The velocity of p-waves emanating from earthquakes is in the range of 5-8 km/s (link)--let's assume it is 5 km/s. The earthquake depth is up to hundreds of kms deep underground (link)--let's assume it ...
8
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2answers
129 views

Earthquakes in Oklahoma influenced by Humans?

I'm currently living in Oklahoma, and there has been an abnormal amount of earthquakes lately, by abnormal I mean more then 5 in a day(not sure if that's normal or not).. I've also been told that in ...
11
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2answers
652 views

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

As we know, earthquakes can be induced by human activities. Can we induce earthquakes around faults regularly so that the energy releases regularly, and hence prevent high magnitude earthquakes by ...
4
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1answer
681 views

Are volcanoes formed from earthquakes?

I know that some earthquakes are caused by volcanoes and that some earthquakes can trigger volcanic eruptions close to where the earthquake is. But what if a great earthquake(8.0 or above) occurs and ...
8
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2answers
265 views

Cross-line fold of a towed-streamer survey

On page 29 of the book 3D Seismic Survey Design by Gijs O. Vermeer, Vermeer says that the equation for a maximum fold in a 3D survey is the following: $M = M_i \times M_c$ where $M_i$ is the inline ...
3
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1answer
148 views

Which component in a 3-component Sp receiver function is the actual Sp RF?

In a 3-component Sp RF I have the green's function in P,SV, and SH. The actual component to the RF that shows the Sp conversion (the one always published in the literature), which would represent as a ...
9
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1answer
279 views

Can a 99.9% probability of an M≥ 5 earthquake within a 3-year period be verified?

Paper: Potential for a large earthquake near Los Angeles inferred from the 2014 La Habra earthquake (2015) Obviously there has been much discussion on the viability of earthquake prediction. This ...
8
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1answer
127 views

Evidence of a seismic trigger of the Storegga Slide ~8.2ka

The Storegga Slide was a catastrophic underwater landslide that occurred off the coast of Norway about 8,200 years ago. This YouTube clip shows simulations that indicate that this slide resulted in ...
5
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2answers
2k views

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 ...
7
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1answer
257 views

Will another big earthquake hit Kathmandu?

Recently, we got the news that the western part of Nepal may be hit by a larger earthquake than that of April 25, because it did release all of its energy. During the earthquake, only the eastern part ...
7
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0answers
322 views

What geological structure(s) is responsible for the recent Queensland earthquakes?

Recently, south-east Queensland has been rattled by 2 moderate earthquakes - a 5.3 a couple of days ago (News report) and a 5.7 tremor just a few hours ago as of writing this post (News Report). These ...
6
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1answer
448 views

Why is it necessary in seismic imaging to calculate an image of reflection coefficients when one of the inputs is the velocity model?

Note: I'm not at all an expert in this field. I read in the first few pages of Robein (2010; Seismic Imaging, A Review of the Techniques, their Principles, Merits and Limitations, EAGE) that both ...
7
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1answer
199 views

Should RTM amplitudes (pre- and post-stack) be related to rock physics properties?

There is as huge uplift in the image quality near and under salt bodies (e.g. the Middle Miocene of the deepwater Gulf of Mexico) by using reverse time migration or RTM. We can now make accurate ...
6
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1answer
105 views

Querying Seismic Databases

I'm trying to find 3-component records of the P-wave arrivals of a variety of earthquakes at seismic stations (specific earthquakes or stations aren't important, I just want a small library of these ...
7
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1answer
82 views

Publicly-available real-time world-wide seismographic information?

Is there a list of websites supplying real time seismographic information for around the world? I could find for specific places. But I'm looking for a list so I can check for anywhere (providing, of ...
32
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3answers
10k views

Is it true that earthquakes are not felt in a cave?

I took a tour of a cave in northern California last weekend. The tour guide asked us, "If an earthquake occurred, what would we feel in here?" My answer was, "fear," but she said we would feel ...
11
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2answers
926 views

Discrete Slant Stack on seismic data

In the formula for slant stacking (tau-p transform) a substitution t=tau+d/v is made. If we consider the substitution as a vector equation then how can vector d/v ...
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1answer
2k views

What is the meaning of seismic spectral blueing?

What is the meaning of seismic spectral blueing? Please cite any good introductory materials if possible.
6
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1answer
461 views

How are the ZNE, ZRT and LQT coordinate systems defined?

I'm confused about the direction of Z (upward or downward?), R (outward or toward the source?) and T.
10
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1answer
2k views

How does one determine the optimum offset in a seismic survey?

I was going through a report on MASW (Multi Station Analysis of Surface Wave) and found this "To avoid the aliasing in the space domain, geophone spacing (Δx) needs to be less than half of the ...