Questions tagged [seismology]
For questions about the study of earthquakes and various seismic sources.
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8 views
Rayleigh waves generation
Good day,
I do not fully understand the physical mechanism of formation of Rayleigh waves at the free surface. While their derivation is quite clear and obey free-boundary conditions, it is not clear ...
6
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1answer
51 views
How sensitive are typical seismometers?
NASA recently landed a seismometer on Mars, with what sounds an impressive detection ability, with press reports gushing it is "able to detect vibrations smaller than a hydrogen atom." A more ...
9
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1answer
54 views
Could an earthquake create a design in a sand pendulum?
Is it possible for an earthquake to generate such a design in a sand pendulum during an earthquake? I saw an article online describing the story of a shop owner finding one of his pendulums had ...
2
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0answers
44 views
Difference between landslide waves and earth quake waves
I am new to this field, recently started working on landslide monitoring mainly in signal processing part. I have the following questions?
1.Will each land slide and every vibration have p wave, s ...
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1answer
37 views
Quality control in Seismic Acquisition - How much data is required?
When it comes to land or marine acquisition (oil exploration, for instance), I can see from literature that quality control (QC) is performed during the survey to ensure that the seismic traces ...
5
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1answer
65 views
Using acoustics to measure the composition, density, and hardness of layers
I am an engineering student at Alfred University and some fellow classmates and I are doing a competition, but one of the tasks we need to complete is autonomously measuring the composition, density, ...
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1answer
79 views
Could glacial melt alter plate tectonic movement?
Let's say some event caused runaway glacial melt, and removed half of the ice currently locked away in specific areas of the planet. Would the significant weight changes on various plates and fault ...
4
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1answer
181 views
Why do major earthquakes keep happening in Lombok recently?
So I've been following the situation in Lombok, Indonesia from both online news and friends on the ground. One thing that I can't seem to figure out is why there are so many earthquakes over an ...
3
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0answers
32 views
statistical methods for analysis of stability tailored for multiple short time series
I am a graduate student of Ecology working on a species diversity problem and am not much educated in time series methods. i have searched 3 general time-series books and could not find a clue on how ...
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0answers
39 views
Seismology - PPV / VDV from geophone waveform data
I'm using an inexpensive seismometer to try and measure the effects of local HGV traffic on buildings. The device is connected to a Raspberry PI that has a Cirrus Logic Audio Card. The signal is fed ...
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1answer
51 views
What does 'reghosted' mean in a seismic cube label?
I came across to a seismic volume labeled as reghosted. In my understanding, a seismic survey is deghosted as part of a processing step. Then I wonder why one would like to reghosted the data? Is ...
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3answers
73 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 ...
3
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1answer
117 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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0answers
20 views
USGS Petersen vs Wielandt Seismic Station Noise Model
The 2002 Wielandt and the 1993 Petersen USGSNew Noise Models are supposed to be equal?.
Why the two shown plots are differents for the New Low Noise Model (NLNM) are different in shape? so they are ...
3
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1answer
174 views
Which type of seismic sensors usually used in Earthquake Early Warning?
As I'm a newbie in seismology and related area, I would like to know which type of seismic sensors usually used in earthquake early warning systems?
4
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1answer
463 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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2answers
264 views
2018 Swan Islands earthquake tsunami
How come the strike-slip 7.6 M earthquake, occurring January 9th, 2018, produced no tsunami? Has there ever been any produced in this region?
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2answers
284 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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0answers
49 views
Problem in identification of seismic event?
I have taken the following synthetic seismogram, generated using Marmousi model, from the Madagascar website.
I could not understand the origin of linear events (present in shot3 after 2 sec) and ...
2
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0answers
169 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 ...
5
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1answer
120 views
Lights associated with earthquakes?
According to the New Madrid, Missouri web site, during the 1811-1812 earthquakes there were reports of lights coming from the ground due to quartz crystals being squeezed. They call this phenomena “...
4
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1answer
1k views
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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343 views
Effects of Mexican Earthquake in San Andreas Fault Line
Could the recent 8.1 Magnitude Earthquake at the Cocos and Nazca plates off the Mexican coast have a knock on effect to the Pacific and Juan de Fuca Plates further north at the San Andreas Fault Line?
5
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1answer
126 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
60 views
Is the centre of Italy still at risk of earthquakes?
I am working on a project which involves taking over a business based in Italy. It is a small village situated near Rieti (Sabina Hills) called Casperia and I am wondering if it is on a fault line? Is ...
3
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1answer
250 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 ...
3
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2answers
352 views
Seismometer records ground displacement or acceleration
I believe Seismometers record ground displacement. However, I have also read in certain articles that this can be ground displacement or acceleration depending on the frequency of the seismometer. ...
3
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1answer
248 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
223 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
62 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 ...
5
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1answer
157 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
101 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 ...
7
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1answer
358 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 ...
7
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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 ...
14
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1answer
1k 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
777 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 ...
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0answers
430 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 ...
7
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1answer
408 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 ...
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1answer
66 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 ...
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1answer
170 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 ...
8
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2answers
146 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
103 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 ...
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1answer
84 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 ...
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1answer
73 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
153 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 ...
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1answer
112 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 ...
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1answer
480 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
717 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
51 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
181 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 ...
