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Datafile Format

Each file contains a header section before the set of unevenly or evenly spaced acceleration, velocity and time values or spectral and period values. The header is designed to provide the user and any programs with information for linking the time histories or spectra to the associated earthquake-, station-, and waveform-parameters and the recording instrument. The following listing shows an example of a corrected time history as archived on the CD-ROM:
	file:                         002727xa.cor
	earthquake code:                 990
	station code:                    694
	waveform code:                  2727
	total number of channels:     3
	orientation of transducer:    NS
	instrument type:              SMACH SM2
	sensitivity:                  20.00V/g
	natural frequency:             10.0Hz
	damping:                       0.670
	full scale amplitude:          0.50g
	resolution of A/D converter:  12bits
	fc of anti-alias filter:       30Hz
	poles of anti-alias filter:    5
	instrument operator:          Swiss Federal Institute of Technology, ...
	time of first sample:         31.12.1999 04:55:53.671UTC
	sampling period:               0.010000s
	number of samples:             3043
	record length:                30.421s
	units:                        m/s*s, m/s & s
	reference:
	Winiger D. (2000): Written communication 27.1.2000. Swiss Seismological Service, ...
	comments & processing history:
	%- pre-processed by: Smit P., Imperial College, London, 2000
	%- processed by: Smit P., Imperial College, London, 2000
	%- transducer response already corrected by instrument
	%-  8th order elliptical bandpass-filter (0.25-25.00Hz)
	%- acceleration time histories filtered
	%- linear baseline of acceleration and velocity time histories corrected
	%- released on CD-ROM: Dissemination of European Strong-Motion Data, 2000
	-> corrected acceleration time histories
	-0.12059E-05 -0.38627E-05 -0.67151E-05 -0.66337E-05 -0.10625E-06  0.78215E-05
	... (sample lines deleted)
	0.40453E-03
	-> corrected velocity time histories
	-0.29815E-05 -0.30068E-05 -0.30597E-05 -0.31265E-05 -0.31602E-05 -0.31216E-05
	... (sample lines deleted)
	0.83948E-05
	STOP

The file-structure of the uncorrected or corrected time histories and spectra as they are archived in the databank is as follow:

Datafile

The following table gives a complete description of the format of the datafiles archived in the databank:

Parameter

Description

Validation

Data Type

RNAME

(primary key)

file name of the time history or spectra as it is archived in the databank and primary key of the record associated with the waveform-database

cannot be missing

A15

RECODE

(primary key)

primary key of the earthquake record archived in the earthquake-database and associated with the time history or spectra

cannot be missing

I6

RSCODE

(primary key)

primary key of the station record archived in the station-database and associated with the time history or spectra

cannot be missing

I6

RWCODE

(primary key)

primary key of the waveform record archived in the waveform-database and associated with the time history or spectra

cannot be missing

I6

NCH

total number of channels associated to this record

cannot be missing

I1

RCMP

orientation of the transducer

cannot be missing

A4

INAME

name of the accelerograph model

missing value is ‘unknown’

A30

ISEN, ISENU

sensitivity and unit of the transducer

missing value is –9.99 and blank

F5.2, A8

IFRE, IFREU

natural, undamped frequency and unit of the transducer

missing value is –99.9 and blank

F5.1, A2

IDAM

damping of the accelerometer transducer, as a proportion of critical

missing value is –9.999

F6.3

IFSC, IFSCU

full scale of the accelerometer transducer and unit

missing value is –9.99 and blank

F5.2, A1

IRES

resolution of A/D converter in bits

missing value is –9

I2

IFC, IFCU

corner frequency of the anti-alias filter and unit for digitally recorded data

missing value is –99 and blank

I3, A2

IPOL

number of poles of the anti-alias filter for digitally recorded data

missing value is –9

I2

SIOP

agency responsible for the operation of the accelerograph

missing value is ‘unknown’

A250

date and time of the first sample

dd.MM.yyyy

dd

RDAY

day of the year of the first sample

1 dd 31

cannot be missing

I2

 

MM

RMONTH

month of the year of the first sample

1 MM 12

cannot be missing

I2

 

yyyy

RYEAR

year of the first sample

yyyy 1933

cannot be missing

I4

hh:mm:ss TMZ

hh

RHOUR

hour of the day, on the 24-hour clock, of the first sample

1 hh < 24

cannot be missing

I2

 

mm

RMIN

minutes of the hour of the first sample

1 mm < 60

cannot be missing

I2

 

ss

RSEC

seconds of the hour of the first sample

0.0 ss < 60.0

missing value is –9.999

F6.3

 

TMZ

RTMU

timezone (usually UTC)

cannot be missing

A10

RPER, RPERU

sampling period and unit for evenly sampled time history

unevenly sampled: -1.0

cannot be missing

F9.6, A3

number of samples

time history

spectra

 

 

 

RNS

number of accele-

ration or velocity

values

SNP

number of

period values

cannot be missing

I5 /

I3

 

 

 

SND

number of

damping values

cannot be missing

I2

RDUR

total duration of digitised record in s

cannot be missing

F7.3

RUNIT

units of the time history-, spectral-, time scale- and period-values (usually m/s2, m/s & s)

cannot be missing

A30

RREF

reference for the time history or spectra

cannot be missing

A250

PRC

comment and processing history of the time history or spectra

%-string at column 1

40A80

Sample array

time history

spectra

 

 

 

sample header

DMP

10

damping value

cannot be missing

F4.1

 

RT

50,000

time values if RPER= -1.0

PER

150

period values

cannot be missing

E12.5 /

E11.3

 

RA

50,000

acceleration values

SA

10150

spectral acceleration

cannot be missing

E12.5 /

E11.3

 

RV

50,000

Velocity

values

SV

10150

spectral velocity

cannot be missing

E12.5 /

E11.3

 

 

 

SD

10150

spectral displacement

cannot be missing

E11.3

 

 

 

PSV

10150

pseudo spectral

velocity

cannot be missing

E11.3

REOF

EOF-marker

STOP

cannot be missing

A4

The following figure shows the distribution of strong-motion records with respect to the trigger date and type of recording instrument:

Distribution 2

Notes on parameters of datafiles:
Filename
The first six characters of the filename of the uncorrected and corrected time histories and response spectra represent the primary key of the waveform-record associated to the record. The next character is a letter referring to the orientation of the transducer azimuth, either X or Y, for the horizontal and Z for the vertical. The last character of the filename separates different versions of digitisation or processing of the same time histories. The extension of the datafile reflects the datatype:
RAW: uncorrected time histories.
COR: corrected time histories,
SPC: response spectra.
Component Direction
The component direction was taken as they were indicated in the header of the original datafiles or as they were reported by the instrument-operators. We did not verify or, if necessary, correct all component direction of all 3,188 individual records. It is therefore recommended to check carefully the component direction if specific positive or negative directions is needed.
Instrument Characteristics
It was not uncommon to have no knowledge of the specific characteristics of the instrument (sensitivity, natural frequency and damping of the transducers, characteristics of the recording instruments, etc.), particularly for the case of old instruments or instruments that have been moved or abandoned, and for temporary stations.
Date and Time of the First Sample
We often could not find any information about the exact date and time of the first sample of the records. If no time information was given, the date and time was set to the source date and time whereas the seconds of the hour of the first sample, RSEC, was set to -9.999. The user is cautioned when using this time information if only the full seconds are given or RSEC is set to -9.999.
Reference
The reference cited in the header of the datafiles and in the waveform-database represents our best available resource for the original time histories and associated parameters. In some cases the reference may be superseded by later work.

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