ah2ml
ah2ml: structure of seismic data in matlab (9/4/91)
written by Tom McSweeney
There is a one-to-one mapping of all data in the AH data structures into
the ML data structures within MATLAB. All header and data information are
stored in the columns of seven arrays. For example the fifth seismogram is
stored in the fifth column of all seven arrays. The first letter of each
array name is upper case and the following letters are lower case.
All arrays except Data have a fixed number of rows.
The Seven ML Arrays
Station Character*20 Code*6,Chan*6,Stype*8
Loc Real*8 Station Lat, Long, Elev; Event Lat, Long, Depth;
Origin time(2)
Calib Complex*62 A0, DS, Poles*30, Zeros*30
Comment Character*362 Event comment*80, Record Comment*80, Log*202
Record Real*6 Abstime(2), Ndata, Sintr, Maxamp, Rmin
Extras Real*21
Data Real*max(Ndata)
Station(1:6,:)' = CODES
Station(7:12,:)' = CHANS
Station(13:20,:)' = STYPES
Loc(1,:)' = Station Latitudes (Geographic degrees)
Loc(2,:)' = Station Longitudes (Geographic degrees)
Loc(3,:)' = Station Elevations (km)
Loc(4,:)' = Event Latitudes (Geographic degrees)
Loc(5,:)' = Event Longitudes (Geographic degrees)
Loc(6,:)' = Event Depths (km)
Loc(7:8,:)' = Event Origin time (eg. 1990.0321,140623.0245 means
3/21/90 14:06:23.0245)
Calib(1,:) = A0 (real part)
Calib(2,:) = DS (real part)
Calib(3,:) = number of poles (real part)
Calib(4,32,:)' = poles (complex)
Calib(33,:)' = number of zeroes (real part)
Calib(34:62,:)' = zeroes (complex)
Comment(1:80,:)' = Event Comment
Comment(81:160,:)' = Record Comment
Comment(161:362,:)'= Log
Record(1:2,:)' = Absolute start time of record (eg. 1990.0321,140623.0245
means 3/21/90 14:06:23.0245)
Record(3,:)' = Number of data
Record(4,:)' = Sample interval (s)
Record(5,:)' = Maximum amplitude of trace
Record(6,:)' = offset time (min) for display purposes only
Extras(1:21)' = extras(0:20)
Data(:,:)' = data (could be real or complex)
Other convenient data structures that are derived from basic data arrays
but are subject to change:
Dist(:)' = epicentral distance (deg, corrected for ellipticity)
Azim(:)' = event to station azimuth (deg, clockwize from north)
Bakaz(:)' = station to event azimuth (deg, clockwize from north)
Stime(:)' = Record start time minus Event origin time (min)
Sintr(:)' = Sample interval
Ttimes(:,:)' = travel times of various phases (min)
Phases(:,:)' = ISC phase codes for times in Ttimes