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In my research, finding and understanding info relating to the lower end of (conventional) surface seismic data acquisition (i.e. 15 - 1 Hz) is relatively simple. However, when I look at specs for a given type of common geophone, signal at and beyond 100 - 120 Hz is not really commented on or ignored altogether. Indeed, it seems that knowing what is real or usable on the upper bandwidth limits of sensors is left alone for reasons I can't fathom.

In light of this, how can we reliably claim that data beyond the upper bandwidth limit of a sensor is usable? For example, I recently read a MASW-related paper ("Enhancing the High-Frequency MASW Method") that used 40-Hz sensors for the study and - as part of the conclusions - declared that "It is remarkable that all dispersion curves curves can be identified up to 1,600 Hz..." Perhaps this is true but I want the proof to support it.

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    $\begingroup$ In your first sentence, do you mean 15 to 100 Hz? And, can you give a reference for the paper? Or see if they say what kind of equipment they are using, because AFAIK a standard MEMS sensor can measure from DC up to about 800 Hz (resonant frequency is about 1 kHz). Perhaps this is some other instrument? $\endgroup$ – kwinkunks Mar 25 at 14:55
  • $\begingroup$ Hi, @kwinkunks. No, I do mean 1 - 15 Hz. I did this to emphasize the two-part meaning to this question and topic. The first being how I always find more research focusing on on the lower end of seismic bandwidth (almost always for some kind of FWI purpose). Secondly, to make the point of how some studies seem to reach too far beyond the usable bandwidth range on the upper frequency threshold of a given geophone. Note the following correction: I meant to put 1000 - 1200 Hz instead of the initial statement above. $\endgroup$ – Nate Benton Mar 28 at 12:26
  • $\begingroup$ (cont.) Looking at specs such as these, you'll see some of the best and most common types of geophones only reach to about 1000 Hz. So, what happens beyond this range? $\endgroup$ – Nate Benton Mar 28 at 12:34
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    $\begingroup$ I can't answer the question fully; but in conventional surface seismics the higher frequencies are attenuated to such a degree that they are hardly present in the data. Thus, while the geophones are capable up to 100+ Hz, the signal just isn't there! This might be why there are relatively few scientific papers about it... $\endgroup$ – Erik Apr 2 at 13:46
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    $\begingroup$ Having said that, the typical frequency bandwidth of a geophone is the frequency range between the resonance frequency and the spurious frequency. For the geophone used in the paper the spurious frequency isn't given (geospace.com/wp-content/uploads/2018/02/… ), but the documentation doesn't necessarily suggest the spurious frequency would lie beyond 1600 Hz... So it is a bit strange. $\endgroup$ – Erik Apr 2 at 13:50

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