BOXER User Guide

Version 3.0

(August 1999)





The "Boxer" program was written by P. Gasperini in the April 1999. It is a revised and simplified version of several computer codes which, starting from 1993, have been developed by the author, and with the contribution of F. Bernardini and G. Ferrari, to compute focal parameters of earthquakes from macroseismic data and have been actually used to make the computation of the Catalogo dei Forti Terremoti in Italia dal 461 a.C. al 1990 [Boschi et al. 1995, 1997] and of the BSSA paper [Gasperini et al., 1999]. The present version of the program also took advantage of important improvements by G. Vannucci and G. Valensise (who also suggested the name of the program).

While the computed macroseismic epicenter, epicentral intensity and azimuth fully coincide with the published papers, the magnitude may be slightly different (some tenth of magnitude unit at most) due to some differences in the relative weighting of intensity classes. A description of the procedure to determine the azimuth and to draw the "boxes" representing the seismogenic structure can be found in Gasperini et al. [1999]. More details on the computation of epicenter and of the magnitude can even be found (but only in italian) in Gasperini and Ferrari [1995,1997]
 
 

Input and output

The program reads optional parameters from the file INPPARM.DAT. The macroseismic data are read instead from a separate file whose name and format can be specified by the user (see below). Both summary data for each earthquake (date, magnitude etc.) and the list of intensity points are read from this file. All the files must reside in the same folder with the program executable. The program writes two output files: a short one on the file OUTSUMMARY.DAT which contains a record for each earthquake including source parameters, magnitude, azimuth , and a long one on file OUTFULL.DAT. See the sample files enclosed in the kit for an example of input and output.
 
 

Option cards in file INPPARM.DAT

Each option cards includes a "tag" field (from column 1 to 10) and a "parameters" field from column 11 to 80. Some option card may be followed by one o more additional "data" cards containing a "parameters" field from column 1 to 80.

The tag identifies the purpose of the card and must be written beginning with column 1 with either upper or lower case characters. A percent character ("%") in column 1 indicate comments and make the card content to be ignored by the program.

An alphabetical list of the available option cards tag follows:

AZPAR - Assign parameters of the azimuth computation algorithm

CRAMCOEF - Assigns coefficient of the distance weighting formula in the azimuth algorithm

FILE - Define the name of the macroseismic input data file

FORMATE - Specifies the Fortran format of the event summary records of the input data file

FORMATI - Specifies the Fortran format of the intensity point records of the input data file

LENGCOEF - Assigns coefficients of the fault length formula

MAGCOEF - Assigns coefficients of the magnitude formula using the radius method

MAPINFO - Direct the program to produce graphic input files for MAP-INFO.

M-I0COEF - Assigns coefficients of the magnitude-intensity formula

OUTLOOK - Direct the program to write a fixed format summary file

OUTPUT - Select type of output

SELMAG - Defines the minimum magnitude for azimuth computations.

USEMAG - Direct the program to use the magnitude reported on the event summary record

WIDCOEF - Assigns coefficients of the fault width formula
 
 

A detailed explanation of the format of each option is given below:
 
 

AZPAR

Assigns the values of the minimum allowed number of data-points and the maximum allowed number of half degree decrements with respect to maximum intensity in the azimuth computation algorithm (see: Gasperini et al. [1999]).

Parameter field:

1)       Name: Nmin

Function: minimum allowed number of data-points

Columns: 11-15

Type: Integer

Default: 3

2)       Name: Ndecr Function: maximum allowed number of half degree decrements with respect to maximum intensity

Columns: 16-20

Type: Integer

Default: 4
 
 

Additional data cards

None

Example

1         11        21
AZPAR         6    4
 
 
 
 

CRAMCOEF

Assigns the values to the coefficients of the CRAM [Berardi et al., 1993] formula to compute the distance weights in the azimuth determination algorithm (see: Gasperini et al. [1999])

where  is the difference between epicentral and local intensity and  is the epicentral distance. Default values were empirically estimated for Italy by Gasperini et al. [1999].

Parameter field:

1)       Name: Acram

Function: a coefficient of the CRAM equation

Columns: 11-20

Type: Real

Default: -0.46

2)       Name: Bcram Function: b coefficient of the CRAM equation

Columns: 21-30

Type: Real

Default: 0.93
 
 

Additional data cards

None

Example

1         11        21
CRAMCOEF  -0.3      1.1
 
 

FILE

Assigns the name of the macroseismic data file containing the event summary and the intensity points.

Parameter field:

1)       Name: Filename

Function: name of the input data file

Columns: 11-80

Type: Alphanumeric

Default: INPUT.DAT
 
 

Additional data cards:

none

Example

1         11
FILE      INPUT2.DAT
 
 

FORMATE

Specifies the Fortran format of the event summary records of the input data file. The format must be embedded in parenthesis. It must contain 9 fields in the following order: Year (integer), Month (integer), Day (integer), Hour (integer), Minute (integer), Second (integer), Epicentral Area (alphanumeric), Magnitude (real), Number of intensity points (integer). Tabulation (T fields) can be used to accomplish this order if different.

Parameter field:

none

Additional data cards:

Card 1

1)       Name: Formate

Function: Fortran format of event summary records

Columns: 1-80

Type: Alphanumeric

Default : (I5, 5I2,15X,A20,1X,F5.1,1X,I5)
 
 

Example:

1         11
FORMATE
(8x,I5,5I3,1X,A20,64x,F3.2,T58,I4)
 
 

FORMATI

Specifies the Fortran format of the intensity point records of the input data file. The format must be embedded in parenthesis. It must contain 4 fields in the following order: Latitude (real), Longitude (real), Intensity (real), Locality name (alphanumeric). Tabulation (T fields) can be used to accomplish this order if different. Latitude and longitude must be given in degrees with decimals (not primes). West longitude is negative. Uncertain intensity values (i.e. VII-VIII) may be given as fractional (i.e. 7.5)

Parameter field:

none

Additional data cards:

Card 1

1)       Name: Formati

Function: Fortran format of intensity point records

Columns: 1-80

Type: Alphanumeric

Default : (2F7.3,1X,F4.1,1X,A20)
 
 

Example:

1         11
FORMATI
(48X,2F8.4,F6.1,T30,A20)
 
 

LENGCOEF

Assigns the values to the coefficients of the formula to compute fault length from moment magnitude

where  is the moment magnitude and  is the fault length in kilometers. Default values are empirical estimates for subsurface rupture length of "all types of fault" according to Wells and Coppersmith [1993].

Parameter field:

1)       Name: Alen

Function: a coefficient of the fault length formula

Columns: 11-20

Type: Real

Default: -2.44

2)       Name: Blen Function: b coefficient of the fault length formula

Columns: 21-30

Type: Real

Default: 0.59
 
 

Additional data cards

None

Example

1         11        21
LENGCOEF  -2.11     0.65
 
 

MAGCOEF

Assigns the values of the coefficients of the Sibol et al [1987] formula to compute the macroseismic magnitude with the radius method (see Gasperini et al. [1999]) for different intensity class. Default values are empirical estimates for Italy from the data of the Catalogo dei Forti Terremoti in Italia dal 461 a.C. al 1990 [Boschi et al.. 1995, 1997].

Parameter field:

1)       Name: Ncoef

Function: number of intensity classes used to compute magnitude

Columns: 11-15

Type: Integer

Default: 10
 
 

Additional data cards

Card 1

1)       Name: Aiv(1)

Function: Lower limit of the intensity class (the higher limit is specified in the next card)

Columns: 1-15

Type: real

Default: see below

2)       Name: Coef(1,1) Function: a coefficient of the Sibol et al [1987] formula

Type: real

Columns: 16-30

Default: see below

3)       Name: Coef(1,2) Function: b coefficient of the Sibol et al [1987] formula

Type: real

Columns: 31-45

Default: see below

3)       Name: Coef(1,3) Function: c coefficient of the Sibol et al [1987] formula

Type: real

Columns: 46-60

Default: see below
 
 

Cards 2 to Ncoef

Repeat the above format for different intensity classes (in increasing order of intensity).

Example:

(The example values are the default ones)

1         11        21        31        41        51        61
MAGCOEF      10
2.             3.554          0.025          0.024
3.             3.422          0.038          0.023
4.             3.034          0.074          0.019
4.5            4.340          0.022          0.015
5.             3.277          0.103          0.012
6.             3.829          0.070          0.015
6.5            4.198          0.094          0.009
7.             4.394          0.091          0.009
7.5            5.078          0.110          0.000
8.             5.348          0.116          0.000
 
 

MAPINFO (undocumented)

Direct the program to produce graphic input files for MAP-INFO mapping code.
 
 

M-I0COEF

Assigns the values of the coefficients of the formula to compute magnitude from epicentral intensity alone when data not enough to apply the radius method (see: Gasperini et al. [1999])

where  is the moment magnitude and  the epicentral intensity. Default values have been empirically estimated on the basis of the italian magnitude-intensity database by Rebez and Stucchi [1999]

Parameter field:

1)       Name: Aint

Function: a coefficient of the M-I0 equation

Columns: 11-20

Type: Real

Default: 0.94

2)       Name: Bint Function: b coefficient of the M-I0 equation

Columns: 21-30

Type: Real

Default: 0.56
 
 

Additional data cards

None

Example

1         11        21
M-I0COEF  1.5       0.5
 
 

OUTLOOK(undocumented)

Direct the program to write a fixed format summary file
 
 

OUTPUT

Select type of output (1- normal output, 2-log output)

Parameter field:

1)       Name: Iout

Function: type of output

Columns: 11-15

Type: Integer

Default: 1
 
 

Additional data cards

None

Example

1         11        21
OUTPUT        2
 
 

SELMAG

Direct the program to compute the azimuth only for earthquakes with magnitude larger than a given threshold.

Parameter field:

1)       Name: Aminmg

          Function: minimum magnitude threshold above which the azimuth is computed

Columns: 11-15

Type: Real

Default: none (no threshold)
 
 

Additional data cards

none

Example

1         11
SELMAG    5.5
 


USEMAG

Direct the program to use the magnitude value specified on the event summary line instead of the computed one.

Parameter field:

none

Additional data cards

none

Example

1         11
USEMAG
 
 

WIDCOEF

Assigns the values of the coefficients of the formula to compute fault width from moment magnitude

where  is the moment magnitude and  is the fault length in kilometers. Default values are empirical estimates for subsurface rupture width of "all types of fault" according to Wells and Coppersmith [1993].

Parameter field:

1)       Name: Alen

Function: a coefficient of the fault width formula

Columns: 11-20

Type: Real

Default: -1.01

2)       Name: Blen Function: b coefficient of the fault width formula

Columns: 21-30

Type: Real

Default: 0.32

Additional data cards

None

Example

1         11        21
WIDCOEF   -1.3      0.29
 
 
 
 

References

Berardi, R., C. Petrungaro, L. Zonetti, L. Magri and M. Mucciarelli (1993). Mappe di sismicità per l’area Italiana, ISMES/ENEL, 51 pp.

Boschi, E., G. Ferrari, P. Gasperini, E. Guidoboni, G. Smriglio and G. Valensise (1995). Catalogo dei forti terremoti in Italia dal 461 a.C. al 1980, ING-SGA, Bologna, 973 pp. and a CD-ROM.

Boschi, E., E. Guidoboni, G. Ferrari, G. Valensise and P. Gasperini (1997). Catalogo dei forti terremoti in Italia dal 461 a.C. al 1990, ING-SGA, Bologna, 644 pp. and a CD-ROM.

Gasperini, P., and G. Ferrari (1995). Stima dei parametri sintetici, in: E. Boschi et al. (Eds.), Catalogo dei Forti Terremoti in Italia dal 461 a.C. al 1980, ING-SGA publ., 96-111.

Gasperini,P., and G. Ferrari (1997). Stima dei parametri sintetici: nuove elaborazioni, in: E. Boschi et al. (Eds.), Catalogo dei Forti Terremoti in Italia dal 461 a.C. al 1990, ING- SGA publ., 56-64.

Gasperini P., Bernardini F., Valensise G. and Boschi E. (1999). Defining Seismogenic Sources from Historical Earthquake Felt Reports, Bull. Seism. Soc. Am., 89, 94-110.

Rebez A. and Stucchi M. (1999). Determinazione dei coefficienti della relazione tabellare Io/Ms, in Catalogo Parametrico dei Terremoti Italiani, ING,GNDT,SGA,SSN, 90 pp..

Sibol, M. S., G. A. Bollinger and J. B. Birch (1987). Estimations of magnitudes in central and eastern North America using Intensity and Felt Area, Bull. Seism. Soc. Am., 77, 1635-1654.

Wells, D. L. and K. J. Coppersmith (1994). New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement, Bull. Seism. Soc. Am., 84, 974-1,002.