Questions tagged [seismology]
For questions about the study of earthquakes and various seismic sources.
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What is the relationship between earthquake risk, magnitude, and distance from the epicenter?
I need a (rough) functional relationship between these three quantities. My initial hypothesis is that the risk $R$ (intended as the probability of a building damage), scales with the square root of ...
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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 ...
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Can the planetary alignment actually affect earthquakes? [duplicate]
We've been hearing a lot these past few days about planes alignments and how it would affect seismology. How scientifically true is that?
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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 ...
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Does the Moon affect earthquakes?
Does the Moon, through factors like its location (if it is at an apsis i.e closest point or furthest point in its orbit) or some changes in density, affect earthquakes on the Earth?
Earthquakes are a ...
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How to quantitively compare two seismic waveform data?
Our group has built an Arduino-based device with an MPU6050 to act as our seismometer for our project, with the data being displayed on Amaseis. Our proctor demands that we quantitively assess its &...
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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 ...
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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 ...
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Estimation of velocity of the wave from seismic trace
How can seismologists estimate velocity (on the different layers) of the wave propogated through the earth , only from given seismic trace(s) ?
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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 ...
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If deterministic wavelet is better for well ties , why do people use statistical wavelet too for wellties?
Synthetic trace generated with deterministic wavelet gives a higher correlation with real seismics.
Though it's more accurate for seismic well ties than statistical wavelet, but there is always an ...
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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 ...
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What is the purpose of wavelet extraction from the seismic trace?
I would love to know what exactly we can do with the extracted wavelet. What kind of information extracted wavelet can contain?
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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 ...
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How well can they localize the sources of these marsquakes using only a single seismometer? Does being in the shadow zone of the core help or hinder?
Phys.org's April 23, 2022 Two largest marsquakes to date recorded from planet's far side links to The Far Side of Mars: Two Distant Marsquakes Detected by InSight which contains the image below.
...
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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 ...
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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 ...
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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 ...
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Source for USGS (probably not) seismic map of La Habra, California (Publication Date April 15, 1998)
I'm trying to find to original source (especially high quality version) of this conservation seismic map. I know that it probably came from USGS (or not) but looks like it out of print? I tried to ...
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Quality control in Seismic Acquisition - shot offset shift
I have a problem with seismic data where the minimum offset of the shot is not centered at the nearest receiver, this shift can be for 3 traces 2 or one and maybe more in the two sides !!
So is there ...
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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 ...
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Where can I find an anisotropic PREM-like model for Earth's interior?
So, I just discovered PREM (the Preliminary reference Earth model) which models the density distribution of matter inside the Earth to any depth.
The PREM is very convenient but since it only depends ...
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Difference between Earthquake Seismographs
How can we tell the difference between a seismograph of a local earthquake and that of a distant earthquake?
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equivalent body force
I am currently reading "Introduction to seismology second edition, and I can't wrap my head around earthquake sources, especially equivalent body force.
What is an “equivalent body force” and how ...
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Horizontal slowness in seismology
I am working on a seismology assignment and it starts with the fundamentals of seismology such as the wave equation, the slowness... such as the question below:
write an equation describing the ...
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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 ...
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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 ...
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Is it possible for Mexico to have a magnitude 9 earthquake?
Everyone has heard of the Cascadia Subduction Zone and the potential threat it poses. However, I have heard nothing about The Cocos Subduction Zone, even though it caused a devastating earthquake over ...
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What would be the phase shift and polarity of a seismic wave upon reflection
What would be the phase shift and polarity of a seismic wave a) when it hit the free surface
b)when the free surface reflection goes down and hit a reflector and returned to the receiver placed on the ...
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What condition(s) need to be met to be able to determine the hypocenter of a microseism?
Today, this XKCD popped up in a chatroom:
comic CC BY-NC 2.5 linked to the source
User Rob mentioned that (as usual with XKCD) this is based on the findings in a research paper.
In Source location of ...
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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 ...
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How do we know the speed of S-waves (shear waves) in the Earth's inner core? Has this been measured?
Wikipedia's Seismic wave includes the plot below of the speed of S and P waves as a function of depth in the Earth. In the region of the outer core the speed of S-waves or shear waves is shown to be ...
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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 ...
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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 ...
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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, ...
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Where can I find broadband seismic reflection data?
or what type of companies should I contact to ask for the data?
This data would be produced from Seismic Vibroseis survey trucks which are mostly used to locate oil and gas.
I doubt most oil and gas ...
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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 ...
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How to read and plot seismic waveform data in Ascii format using Obspy?
I wish to plot seismic waveform data using Obspy, bu they are in Ascii format. Is it possible to read and plot Ascii file using Obspy?
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Using an accelerometer as a geophone to conduct a seismic survey
I am doing a capstone project for a sensor systems course and I would like to write a python program to acquire, process and present seismic data like that of seismic surveys. Is it possible using ...
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Zoeppritz equations derivation
I have been long looking for the derivations and step by step explanation of Zoeppritz matrix but either internet is full of final versions or I can’t find it...I would be very thankful if anyone can ...
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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 ...
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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 ...
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Wave train 200 m/s meaning
I ran a 60 m line intended for surficial seismic refraction. Energization with hammer. 12 (10 hz vertical 5 m spaced) geophones and 5 shots (15 m spaced). Record length 0.5 s. Thanks to a borehole ...
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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 ...
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wave speed is smaller than both horizontal wave speed and vertical wave speed?
I am new to GIS and just get the idea of slowness. I can understand why people need the slowness in GIS rather than just the reciprocal of velocity. However, I feel the definition of slowness is weird ...
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reverse time migration for wave equation PDE using SBP-SAT
I'm stuck implementing a reverse time migration technique, the PDE(partial differential equation) being implemented is an acoustic wave equation, The numerical method being used is a FD(finite ...
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What are "young thrust faults" and how does one identify them on the Moon?
The abstract of the new Nature Geoscience paper Shallow seismic activity and young thrust faults on the Moon reads:
The discovery of young thrust faults on the Moon is evidence of recent tectonic ...
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How does multiple layer seismic reflection work? How do we distinguish arrivals from different layers and their velocities?
Whenever we are investigating multiple layer interfaces in a seismic reflection survey the root-mean-squared velocity is often employed to deduce travel time to a certain n-th layer and also to deduce ...
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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 ...
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Near-Surface Investigations: FWI vs. MASW
MASW is a common processing method for civil/geotechnical and even for oil/gas exploration (usually weathering static corrections) applications. In my experience, it seems to work well for most ...
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