[Qopen] for local earthquakes (less then 70 km)

[Petr Predein]

Thank you so much for detailed answer and very useful instruction with
examples. I really appreciate it! I also find Qopen package works for me
and hope the result will not put me to shame. Thanks!

ср, 15 янв. 2020 г., 17:10 Tom Eulenfeld <tom.eulenfeld at uni-jena.de>:

> Hello Petr,
>
> please use "[Qopen]" keyword in the subject when posting a message to
> the mailing list. Then, it its categorized correctly and automatically
> accepted.
>
> The choice of Sens-Schönfelder and Wegler (2006) is comprehensive in
> their setting. Still, it is IMHO absolutely no problem to use shorter
> distances. I have done it myself. Your dataset appears suitable. Please
> take the following in mind:
>
> 1. v0 can be set to another velocity, it should be a "mean" value for
> the used model, also time windows need to be adapted.
> 2. The resulting Q-values for scattering and intrinsic attenuation will
> be "mean" values over the sampled volume. This means Q-values will
> depend on the scale of the dataset and used time windows.
> 3. For local datasets with small earthquakes, results for low
> frequencies will not be useful.
>
> Setting the time windows in your config is a bit of trial and error. The
> direct S wave window should cover the the complete S wave train, and the
> coda window best starts at the end of the S wave window.
>
> For your convenience, I append the config files I used for the USArray
> (Eulenfeld and Wegler, 2017) and the config files for the different
> regions investigated in Eulenfeld and Wegler (2016).
>
> Even for a successful inversion, have a look at the log file and watch
> out for errors.
>
> I hope you will find the package and these hints useful.
> Best regards!
>
> Tom
>
>
>
>
> On 15.01.20 03:51, Petr Predein wrote:
> > Hello, I am new to this mailing list, and very interesting in using
> > Qopen package for calculating intrinsic and scattering attenuation.
> > And my question to respected community is, can I use earthquakes with
> > epicenter very close to some station, with magnitudes no more then
> > 3-3.5, for example.
> > Normally, I read in (Sens-Schönfelder C., Wegler U., 2006: Radiative
> > transfer theory for estimation of the seismic moment, p. 3)
> > that hypocentral distance should be greater than 60 km, because it is
> > inappropriate to use mean velocity of S-waves about 3.5 km/s for shorter
> > distances (upper layers of the Earth crust?)
> > But it is also shown that Qopen uses improved method, unlike original
> > (Sens-Schönfelder C., Wegler U., 2006).
> > Also, I understand that it's incorrect one cannot use earthquakes with
> > epi distances less then several km up to 10 km, depending on frequency
> > range.
> > Finally, can I use Qopen for small earthquakes with epicentral distance
> > from 10 to 70 km? (average depth is in range 15-20 km, hovewer).
> > And, if yes, which setting should I use in conf.json file to avoid big
> > errors, with stations on free surface.
> > Thanks in advance!
> >
>
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