• Antelope Release 5.5 Linux 2.6.32-220.el6.x86_64 2015-04-21

 

NAME

dbdepest - estimates depth to Moho from a receiver function

SYNOPSIS

dbdepest z1 z2 dz Vcrust Fmin Fmax Delta Tfit Zbasin VpVs tshift inwf_file subset_rf [depest.pf] 

SUPPORT


Contributed code: NO BRTT support.
THIS PIECE OF SOFTWARE WAS CONTRIBUTED BY THE ANTELOPE USER COMMUNITY. BRTT DISCLAIMS ALL OWNERSHIP, LIABILITY, AND SUPPORT FOR THIS PIECE OF SOFTWARE.

FOR HELP WITH THIS PIECE OF SOFTWARE, PLEASE CONTACT THE CONTRIBUTING AUTHOR.

DESCRIPTION

Reads a receiver function stored in a css3.0-database, and using a grid search method estimates the crustal thickness that best fits that receiver function in a sum-of-squares sense. The crustal thickness is varied in a simple crustal model to find that which best predicts the observed waveform. See Sheehan et al. [1995, JGR] for longer explanation and tests of an earlier version of this program.

Model receiver functions are calculated, for each set of descriptive parameters, using a propagator-matrix estimate of crustal response to incident plane waves at its base. The model includes a single crustal layer, of specified velocity, and optionally a shallow basin. Assumed parameters include mantle P and S velocities of 8.0 and 4.62 km/s, mantle density of 3.3 g/cc, basin P velocity of 3.9 km/s, basin density of 2.4 g/cc. Vp/Vs is specified if there is no basin, or set at 1.73 if there is (the specified Vp/Vs then applies to the basin). Crustal density is estimated from a linear fit to Nafe-Drake empirical curves.

COMMAND LINE ARGUMENTS

OUTPUT

EXAMPLE

dbdepest 25. 65. 2. 6.5 .04 .2 35. 30. 4. 2.0 0. lmndb.wfdisc 0

Estimates crustal thickness every 2 km from 25 to 60 km depth. Assume a crustal thickness of 6.5 km/s, bandpass signals from .04 to .2 Hz, assume a 35 degree incidence angle, fit the first 30 s of record, assume a 4 km thick basin with Vp/Vs = 2.0. No phase shift was placed in the records; the first wfdisc record (0) is taken out of the database lmndb.

LIBRARY

-ltr -ldb -lstock -lcoords -ltttaup -lm -lteles

BUGS AND CAVEATS

Most of the details and parameter conventions were done to finish the Rocky Mt. paper and should be made more general. As well, a better scheme needs to be worked out to allow more complicated crustal models, grid searches over other parameters, etc.

Filtering, especially low-pass filtering, is very important as at high frequencies the synthetic seismogram calculation is unstable.

AUTHOR

Geoff Abers, Boston University; some help from Anne Sheehan, CU, on an earlier version. The origin of the propagator matrix routines are lost to history.
Antelope User Group Contributed Software
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