MLOC bloc File

~.bloc File

A ~.bloc output file is only created through use of the bloc command. It has a very specialized purpose, to assist in the use of the hypocenters determined in an mloc relocation as “priors” in BayesLoc. This is only likely to be of interest in the case of a calibrated mloc relocation.

The idea behind this command was that combining mloc and BayesLoc in this manner might be a useful way to leverage the value of a limited number of calibrated hypocenters to obtain improved catalogs of seismicity over a broader region. This was explored in Ezgi Karasözen’s PhD Thesis. If you are interested in this research contact Ezgi to discuss it in more detail.

Conversion of the ~.bloc file

The ~.bloc file cannot be directly used in BayesLoc. It is converted to a BayesLoc origin_prior.dat file by the command:

awk '{print "1000"NR"\t"$2"\t"$3"\t"$4"\t"$5" \t"$6"\t"$7"\t"$8}' *.bloc > mloc_priors.dat

In BayesLoc these values will be interpreted as:

ev_id, lat_mean, lon_mean, dist_sd, depth_mean, depth_sd, time_mean, time_sd

It may still be necessary to change the ev_id (event ID). This example uses a simplistic ev_id that starts from 100001. If a parameter is assumed to be known without error, you can assign 0 to the corresponding standard deviation. If you don’t trust the information you are inputting, you can assign -1 to the standard deviation. For example, if you want Bayesloc to ignore the focal depths from the ~.bloc file, you would write “-1” to the depth_sd column. Here is an example. One line from ~.bloc is:

20180812.1458.53  69.55582  214.79987        1.378   11.0    4.0       1534085933.336  0.20

which when converted to Bayesloc input is:

100001 69.55582 214.79987 1.378 11.0 4.0 1534085933.336 0.20

Converting a Station File

It may be desired to use the station information from mloc in BayesLoc. This is done by extracting the section of mloc’s ~.stn file that lists all stations used in the relocation and reformatting:

awk '{print $1, $2, $3, $4/1000}' mloc_stations.dat > bayesloc_stations.dat

Converting Arrival Time Data

If you need to convert mloc’s arrival time data (MNF v1.3) for use in BayesLoc, contact Ezgi Karasözen.