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# Seismotectonics - Science topic

Explore the latest questions and answers in Seismotectonics, and find Seismotectonics experts.

Questions related to Seismotectonics

Is there any relation between the shape of the elliptical earth and the prediction of the epicenter of earthquakes?

There are many causes of earthquakes. Tectonics plates and geodynamic conditions control the earthquake occurrence in active regions. Thus monitoring the subsurface conditions clearly help us to predict an earthquake epicenter. It is well known that the energy explodes in weak regions, fractured area or the most easiest break up part of earth.

I wanted to check the completeness of an earthquake catalog. I saw the paper "

**Probabilistic Seismic Hazard Analysis for Rock Sites in the Chennai City" by G. Kalyan Kumar**and it used the**Visual Cumulative Method (CUVI).**But I do not know how to identify mathematically or via excel the first point "when the slope of the cumulative fitting curve can be well approximated by a straight line"Is there a GMT script for plotting

**ternary diagram**of Global CMT*psmeca*input (https://www.globalcmt.org/CMTsearch.html)? Like the one shown in the first figure.I've been using FMC (https://josealvarezgomez.wordpress.com/2014/04/22/fmc-a-python-program-to-manage-classify-and-plot-focal-mechanism-data/) but I can't customize it such that it can also show the depth for each seismicity.

As you know that Mw is related to released energy for specific earthquake, so why their recorded accelerations vary for the same distance and Mw for different seismotectonic regions?

It is very important to study the time-acceleration history for all seismotectonic units in all overall the world to establish new type of ground motion attenuation and for data truth.

regards

When we study the seismicity of any region we need to build a trustable caatalog.

Could you please explain these optimal parameters of earthquake clustering?

how to build on these seismic clustered sources?

For a relative large event, it usually has several sub-events and we get a large set of data. In order to do stacking or for visualization purpose, it's better to flip the traces with opposite polarity. Could you tell me some simple and effective method to detect it. Some crude method like finding the maximum on displacement record usually failed if the waveform is complex. Thanks!

I need help to deconvolute Simulated Earthquake Data (created from Response Spectra data of IS :1893-2002)

**Target Spectra**I am applying the input motion at the surface and recording the Time History Data at Bed rock level both in STRATA and DEEP SOIL.

But:

1) I am not sure whether to give input motion as WITHIN or OUTCROP motion.

2) If I re-convolute the Time History Data obtained at Bedrock to Surface Level then the recorded Time History at surface is not matching the Target Spectra Data.

Some think that 25 December 2016 magnitude 7.7 earthquake might be aftershock of the 1960 M9.5 earthquake. My question is how M7.7 earthquake could be considered aftershock? Isn't it too big for aftershock? To me, there should be upper limit of the magnitude of the aftershock!
Anyone help me to understand this phenomenon.

Best,

Mehmet

Hi,

This picture is about a Gigantic Human Skeletons Found In The Nepal Mountains After Massive Earthquake?!

What about the second and the third picture...it is true these stories?

Best regards

Hakima

In the lead-zinc deposits concentrate area, the seismic profile of an area has been explained. From the interpretation of the seismic profile, a series of thrust folds are formed in the deep structure of this area, mainly in the compressive stress setting,How to combine the interpretation of seismic profile with regional tectonics and geological structure of mining area more deeply?I should specifically from what aspects to carry out the next research work?

The wave diagram has been attached herewith.What is the reason of such wave?Is it noise or signal?

Some believe it is 30 cm and some 50 cm. I did not find a research article which describe the maximum safe depth of tsunami flow ( minimum tsunami depth which a man can stand without falling). If you know a good reference, please be kind to share the link.

Dear researchers

How can I determine the predominante frequency of an earthquake from it ground acceleration record using MATLAB.

Best regards.

Any suggestions on how to measure the thickness of the interlayer between the "brucite-like" layers in hydrotalcite minerals? Are these types of measurements being made, or do we need to do calculations? I have a rough idea of the spacing, as carbonate ions and water fit in, but could the spacing be more? I need to figure out what can fit in there, and maybe chemical engineers can help (I am a geologist)?

Thanks in advance!

I need some information to study active tectonic in shore lines and coastal area. please help me and send me some papers are useful in this path.

I need some information about tectonic and seismotectonic study in coastal area. what are the software to study earthquake pattern and other seismotectonic study in shore line and coastal area?

Could you please let me know, where can I find most reliable Seismic data related to deep Earthquakes?

Can anybody inform the correlation between "Richter scale" for seismic vibration measurement (earthquake measurement) , Vs the "g" scale i.e. the acceleration , Vs the "Freq. range" .

Some Seismic sensor OEMs provide the output in terms of "g" , and the "Frequency response range". However they do not provide correlation in terms of "Richter scale" .

Also , which frequencies are more significant for a "earthquake vibration measurement sensor " to consider in its range ?

We have been recording seismic activity in a high gradient temperature zone near a craton. This activity was not previously noticed until an industrial application started pumping big amounts of water into the deep aquifer. Could a temerature "shck" cause the seismic tremors?.

John

This is for tsunami initiation according to Okada's formulas. Should be easy for students.

Hypothetically calculating the impact of a co-seismic landslide on a railway bridge we have: (the probability of the earthquake multiplied by the models epistemic uncertainty multiplied by the probability of a landslide multiplied by its associated epistemic and aleatoric uncertainties. Are the latter two uncertainties dealt with as separate entities or should they be combined before running the entire equation?

So should it be Peq X Peqepi X Pls X Plsepi X Plsale = Hazard exposure

or

Peq x Peqepi x Pls x (Plsepi x Plsale) = Hazard exposure

where Peq = prob earthquake, PZepi is PZ epistemic uncertainy & PZale = aleatoric uncertainty

Furthermore should the aleatoric uncertainty be a larger decimal or a smaller one for seismic hazard as this will impact the model severly? ie 0.9 or 0.1.

This is concerning earthquake analysis of multistoried building.

I have two random signals from earthquake acceleration. These signals are approximately similar and comparable.

I need to convert one of them to another by a mathematical or statistical approach and find a functional correlation between these signals.

The source parameter of an earthquake ( like Moment (Mo), stress drop (sigma), source radius (r), Magnitude (Mw) etc.) can be derived simply from the corner frequency of the recorded seismogram.

Questions...

1.) why corner frequency is so important in calculation of source parameters as compared to the strength (magnitude) of the frequency content of the seismogram?

2.) The seismogram records only a fraction of the energy released by an earthquake. Is it correct to estimate moment/magnitude/energy/source radius etc. from the recorded seismogram?

A young student asked to me if it will be possible a M=12 earthquake in terms of moment magnitude. I told him that the only limit should be not to have a method to estimate well earthquake magnitudes at this level. But probably for the internal Earth layering and properties and the actual thermal equilibrium it is quite impossible to have a M=12. However I have no knowledge of papers or assumptions that discuss about a physically plausible moment magnitude upper bound.

I have few near-field ground motion records having a range of 100-150cm/sec PGVs. can we find out which ground motion was recorded forward and backward? Also, does ground motions recorded backward have high velocities of the above range?

Can anybody please explain the detailed procedure in order to obtain the richter magnitude equation for a particular region.

The question concerns seismicity, its spatiotemporal distribution and different models of viewing foreshocks ...

Wills and Coppersmith provided relations to estimate rupture parameters for a fault source which can relate magnitude with rupture length and area. Are there any such relations to assess areal rupture parameters like "Depth to top and Depth to bottom of rupture", "Rupture width" and others?

Image attached is a trace plot of (acceleration, velocity, displacement) fault normal and fault parallel component of Northridge-Rinaldi ground motion. Can we say something looking at the image?

Are such small magnitude earthquakes (current seismicity) accepted to correlate them with the neotectonics of the region? If yes, then please elaborate how one should approach, but if no, then please recommend other applications and scope in this regard.

For example, I need to know from a recorded data

if it is a near-fault or far-fault...

if near-fault, fault normal or fault parallel...

if fault normal, is it caused by a dip-slip or strike-slip...

if dip-slip normal or reverse, and is it recorded on hanging wall or foot wall?

So just with a recorded data, is it possible to obtain all these parameters, if so how?

Can someone help me in explaining why, when speaking about directivity effects, it is spoken only on velocity time history and not using acceleration time history?

I could understand why fling effects are spoken using only displacement time history, but need to understand why velocity profile is used for directivity? Also, looking at the velocity profile, can we say if it is backward rupture directivity or forward rupture directivity?