Questions tagged [seismology]
For questions about the study of earthquakes and various seismic sources.
201 questions
5
votes
1
answer
268
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, ...
- 51
5
votes
1
answer
565
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 ...
- 167
5
votes
2
answers
206
views
Can an igneous rock have a Vp of less than 1000 m/s and need blasting to excavate?
I have run a 60 m refraction seismic line on a mountain summit. The environment was noisy (wind would be the principal agent) and quite difficult to pick first arrivals. It resulted in 800 m/s.
A ...
5
votes
1
answer
75
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 ...
5
votes
1
answer
99
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,...
- 183
5
votes
2
answers
920
views
Performing time-frequency analysis (FTAN)
I am trying to do ambient noise tomography and I am quite confused on how to perform time-frequency analysis (FTAN) as shown in figure 13b and 13d of this paper by Bensen et al.. I am using Python and ...
- 151
5
votes
1
answer
158
views
What are today's methods in calculating the Local Magnitude of earthquakes?
I'm no expert and barely have any idea about this. But I want to know if the methods in calculating the Local Magnitude can only be done manually? I mean manually by first reading a seismograph, ...
- 51
5
votes
0
answers
134
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 ...
- 51
4
votes
2
answers
1k
views
Do planetary alignments affect Earth's seismic activity?
There is a widely circulated tweet by Frank Hoogerbeets where it seems he has predicted Turkey's earthquake a few days before. The tweet says:
Sooner or later there will be a ~M 7.5 #earthquake in ...
- 143
4
votes
2
answers
2k
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 ...
- 153
4
votes
1
answer
518
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 ...
- 173
4
votes
1
answer
178
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 ...
- 15.5k
4
votes
2
answers
1k
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 ...
- 133
4
votes
1
answer
103
views
What's the strongest earthquake we currently can miss observing on Earth?
Reading jeffronicus' answer about how seismic stations record bomb explosions, particularly the reminder that the intensity of earthquakes drops by distance, made me start wondering what scale of ...
- 8,827
4
votes
2
answers
178
views
Is it reasonable to approximate the swinging building (base of the building) during an earthquake to a simple harmonic motion?
I am thinking of making a model of swinging building during earthquake and study the methods to minimize the swinging.
So does it even makes sense to approximate the swinging buildings (the base of ...
- 41
4
votes
1
answer
1k
views
Where can I download historical sesimic data in CSV/Excel format for processing in R?
I'm not familiar with these kinds of data sets but I'm looking for some data for a project I'm working on. Essentially I would like multiple time series of seismic data from different stations over ...
- 41
4
votes
1
answer
260
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 ...
- 6,904
4
votes
1
answer
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 ...
- 43
4
votes
1
answer
72
views
What is the pitch and roll in a tiltmeter sensor?
I wonder if you could help me to understand what the pitch and roll mean for an tiltmeter sensor? I have tiltmeter data and I don´t understand at all how it works. If you can recommend literature on ...
- 395
4
votes
1
answer
215
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 ...
- 43
4
votes
1
answer
363
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 ...
- 41
4
votes
1
answer
55
views
Where could I get waveform data on low-frequency earthquakes, very low-frequency earthquakes, volcanic tremor and non-volcanic earthquakes?
I am a marine geology masters student and I am writing my thesis on slow earthquakes. I will include graphs of the most common types of earthquakes:
Low-frequency earthquakes
Very low-frequency ...
- 395
4
votes
1
answer
164
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 ...
4
votes
0
answers
84
views
Why on Earth are there observatories on the active Mauna Loa?
Near the summit of Mauna Loa there are two observatories. Mauna Loa is an active volcano that is being watched, so why did they build observatories up there instead of building them on the dormant and ...
- 173
4
votes
0
answers
36
views
Seismicity associated with post glacial rebound
Allied to the question: Why is relative sea-level falling in Hudson Bay?, where the surviving answers mention post glacial rebound.
Is seismicity associated with post glacial rebound and if so what is ...
- 25k
4
votes
0
answers
111
views
Book recommendation on waves
I am looking for a book about waves in the context of Earth Science, the two main topics I have in mind are ocean waves and seismic waves.
Explanations in a book like Understanding earth1 is too ...
4
votes
0
answers
44
views
Why core refracted phases like SKS polarise vertically when P to S conversion happens in the Core-Mantle boundary?
While working on investigation of seismic anisotropy I came to know that core refracted phases like SKS or SKKS polarise vertically when P to S conversion happens in the Core-Mantle boundary. Why is ...
4
votes
0
answers
254
views
Beam forming FK analysis of a seismic wave
So after reading alot of literature on source localization, I found out that FK analysis is one of the most widely used methods to determine source location without explicitly calculating the ...
- 141
4
votes
0
answers
185
views
Small earthquake happening every night at the exact same time
I experience this weird feeling for the last three months. Every night, at exactly 3AM I can feel small earthquake and I could not find anything on the internet related to it. Does anyone have any ...
- 41
4
votes
0
answers
141
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 ...
- 51
4
votes
0
answers
77
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 ...
- 41
4
votes
0
answers
43
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 ...
4
votes
0
answers
174
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 ...
- 41
3
votes
4
answers
387
views
Do we know anything about the nature of Earth's core that hasn't come from magnetic or seismic measurements?
There is much known about Earth's core from painstaking analysis of seismic data, and from detailed magnetic field maps and trends over time.
Are there any other measurements that have contributed to ...
- 6,904
3
votes
2
answers
70
views
Would climate change result in an increase in seismic activities?
Would climate change result in an increase in seismic activities?
I can see two potential forces acting:
Temperature dilation of the Earth's surface.
A change in the distribution of water mass, fewer ...
- 133
3
votes
3
answers
128
views
Is an Earthquake Large Enough to Cripple the Entire West Coast of North America Possible?
I have an idea for a novel I want to turn into a reality, and I'm starting some research first to make my book at least plausible in very specific conditions. The main aspect of the story would be ...
- 31
3
votes
2
answers
2k
views
Travel Times for Seismic Wave Types - Why reflected t-x plot curves
I do not understand how the reflected wave in a seismic survey has a steepening slope (slows down) Please bear with me as I lay out my thoughts because I feel like I can grasp all of this except this ...
- 303
3
votes
1
answer
292
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?
- 149
3
votes
1
answer
130
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
votes
2
answers
1k
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. ...
- 213
3
votes
2
answers
61
views
Where can I access public sonic well-log data?
I'm doing some research and I'm in need of some well-log data from a sonic tool. I'm specifically looking for a multi-receiver tool with 6 or more receivers if possible.
I've been able to find a lot ...
- 111
3
votes
1
answer
79
views
Difference between Earthquake Seismographs
How can we tell the difference between a seismograph of a local earthquake and that of a distant earthquake?
- 161
3
votes
1
answer
519
views
How to determine the number of bytes in the SEGD Revision 1 interblock gap
How can one determine the number of bytes in the SEGD Revision1 interblock gap?
The quantity is present on page 5 of the standards document.
- 175
3
votes
1
answer
66
views
Is there any free indexed journal that Geoscience students can publish?
I am planning to publish a paper related in Geoscience/Geophysics/Seismology within scope of Machine Learning/AI in particular. Is there any Journal that provide free article publishing for ...
- 51
3
votes
2
answers
120
views
Seismic velocity relations
I do understand why the seismic velocity decreases with temperature and increases with pressure, but I am not really familiar with the relationship between the velocity with Poisson's ratio. I ...
- 91
3
votes
1
answer
129
views
The longest interval between earthquake main shock & after shock
On August 21, 2022, the Western Australian town of Cadoux experienced a magnitude 4.4 earthquake. According to the report of the incident, that earthquake might be an aftershock of a magnitude 6.1 ...
- 25k
3
votes
2
answers
312
views
Does the Earth produces measurable gravity waves?
Does the Earth exhibit measurable gravity waves? Note: I'm not asking about gravitational waves.
Some recent experiments looking at low-frequency (3$\times 10^{-5}$Hz) accelerometer data are showing ...
- 41
3
votes
1
answer
130
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 ...
- 31
3
votes
1
answer
4k
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 ...
- 33
3
votes
1
answer
204
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 ...
user6354