NCEDC

Database structure

This chapter defines the physical structure of each table, as it exists within the DBMS data dictionary. The name of the relation appears in bold print at the top left and a description of the table at the top right. Bold attributes represent primary keys, italic attributes represent foreign keys, and underlined attributes stand for CSS attributes.

Event Summary information on an event
Attribute	Type	Description
evid	int	Event identifier
prefor	int	Preferred origin
prefmag	int	Preferred magnitude
prefmec	int	Preferred mechanism
commid	int	Comment identifier
auth	char(15)	Source/originator
subsource	char(8)	Subsystem source
etype	char(7)	Event type
selectflag	int	"Definitive" definition of the event
version	int	Event version number
lddate	date	Load date

Significant_Event Summary information on a significant event
Attribute	Type	Description
evid	int	Event identifier
evname	char(80)	Event name
remarks	char(2)	Event indications (felt, damage, ...)
nfelt	int	Number of felt reports
mmi	int	Maximum MM intensity
pga	float	Peak acceleration
lddate	date	Load date

Origin Data on event location
Attribute	Type	Description
orid	int	Origin identifier
evid	int	Event identifier
prefmag	int	Preferred magnitude
prefmec	int	Preferred mechanism
commid	int	Comment identifier
bogusflag	int	Bogus origin flag
datetime	float	Origin date
lat	float	Estimated latitude
lon	float	Estimated longitude
depth	float	Estimated depth
type	char(2)	Type of location
algorithm	char(15)	Location algorithm used
algo_assoc	char(80)	Associator algorithm used
auth	char(15)	Source/originator
subsource	char(8)	Subsystem source
datumhor	char(8)	Datum type for latitude & longitude
datumver	char(8)	Datum type for vertical
gap	float	Maximum azimuthal gap of stations
distance	float	Distance to nearest station
wrms	float	Standard error of observations
stime	float	Origin time error
erhor	float	Horizontal error
sdep	float	Depth error
erlat	float	Error in latitude
erlon	float	Error in longitude
totalarr	int	Total number of arrivals
totalamp	int	Total number of amplitude readings
ndef	int	Number of locating phases
nbs	int	Number of S readings
nbfm	int	Number of P first motions
locevid	char(12)	Local event identifier
quality	float	Quality of solution
fdepth	char	Fixed depth
fepi	char	Fixed epicenter
ftime	char	Fixed time
vmodelid	int	Velocity model identifier
cmodelid	int	Crustal model identifier
rflag	char	Human/automatic/finalized observation
lddate	date	Load date

Origin_Error Error data on event location
Attribute	Type	Description
orid	int	Origin identifier
sxx	float	Covariance matrix element
syy	float	Covariance matrix element
szz	float	Covariance matrix element
stt	float	Covariance matrix element
sxy	float	Covariance matrix element
sxz	float	Covariance matrix element
syz	float	Covariance matrix element
stx	float	Covariance matrix element
sty	float	Covariance matrix element
stz	float	Covariance matrix element
azismall	float	Azimuth of smallest principal error
dipsmall	float	Dip of smallest principal error
magsmall	float	Magnitude of smallest principal error
aziinter	float	Azimuth of intermediate principal error
dipinter	float	Dip of intermediate principal error
maginter	float	Magnitude of intermediate principal error
azilarge	float	Azimuth of largest principal error
diplarge	float	Dip of largest principal error
maglarge	float	Magnitude of largest principal error
lddate	date	Load date

Netmag Summary information on a magnitude
Attribute	Type	Description
magid	int	Magnitude identifier
orid	int	Origin identifier
commid	int	Comment identifier
magnitude	float	Magnitude
magtype	char(6)	Magnitude type
auth	char(15)	Source/originator
subsource	char(8)	Subsystem source
magalgo	char(15)	Magnitude algorithm
nsta	int	Number of stations used
uncertainty	float	Magnitude uncertainty
gap	float	Maximum azimuthal gap of stations
distance	float	Minimum distance of stations
quality	float	Subjective quality
rflag	char	Human/automatic/finalized observation
lddate	date	Load date

Arrival Summary information on a seismic arrival
Attribute	Type	Description
arid	int	Arrival identifier
commid	int	Comment identifier
datetime	float	Pick date
sta	char(6)	Station code
net	char(8)	Network identifier
auth	char(15)	Source/originator
subsource	char(8)	Subsystem source
channel	char(3)	Channel name
channelsrc	char(8)	Domain of channel name
seedchan	char(3)	SEED channel name
location	char(2)	SEED location
iphase	char(8)	Reported phase
qual	char	Signal onset quality
clockqual	char	Clock quality
clockcorr	int	Clock correction
ccset	char	Clock correction set
fm	char(2)	First motion
ema	float	Emergence angle
azimuth	float	Observed azimuth
slow	float	Observed slowness
deltim	float	Delta time
delinc	float	Error in angle
delaz	float	Delta azimuth
delslo	float	Delta slowness
quality	float	Quality
snr	float	Signal to noise ratio
rflag	char	Human/automatic/finalized observation
lddate	date	Load date

AssocArO Data associating arrivals with origins
Attribute	Type	Description
orid	int	Origin identifier
arid	int	Arrival identifier
commid	int	Comment identifier
auth	char(15)	Source/originator
subsource	char(8)	Subsystem source
iphase	char(8)	Associated phase
importance	float	Importance of phase
delta	float	Station to event distance
seaz	float	Station to event azimuth
in_wgt	float	Input weight
wgt	float	Output weight
timeres	float	Time residual
azres	float	Azimuth residual
emares	float	Incidence angle residual
slores	float	Slowness residual
vmodelid	int	Velocity model identifier
scorr	float	Station correction in seconds
sdelay	float	Station delay
rflag	char	Human/automatic/finalized observation
ccset	char	Clock correction set
lddate	date	Load date

Amp Summary information on an amplitude reading
Attribute	Type	Description
ampid	int	Amplitude identifier
commid	int	Comment identifier
datetime	float	Amplitude date
sta	char(6)	Station code
net	char(8)	Network identifier
auth	char(15)	Source/originator
subsource	char(8)	Subsystem source
channel	char(3)	Channel name
channelsrc	char(8)	Source of channel name
seedchan	char(3)	SEED channel name
location	char(2)	SEED location
iphase	char(8)	Reported phase
amplitude	float	Amplitude
amptype	char(8)	Amplitude type
units	char(4)	Units of amplitude
ampmeas	char	Amplitude measure
eramp	float	Error in amplitude
flagamp	char(4)	Flag to indicate whether amplitude is over P packet,S packet,entire waveform.
per	float	Period
snr	float	Signal to noise ratio
tau	float	Coda duration (F-P time)
quality	float	Subjective quality
rflag	char	Human/automatic/finalized observation
cflag	char(2)	Clip flag
wstart	float	Start of time window
duration	float	Duration of amplitude reading
lddate	date	Load date

AssocAmO Data associating amplitudes with origins
Attribute	Type	Description
orid	int	Origin identifier
ampid	int	Amplitude identifier
commid	int	Comment identifier
auth	char(15)	Source/originator
subsource	char(8)	Subsystem source
delta	float	Station to event distance
seaz	float	Station to event azimuth
rflag	char	Human/automatic/finalized observation
lddate	date	Load date

AssocAmM Data associating amplitudes with magnitudes
Attribute	Type	Description
magid	int	Magnitude identifier
ampid	int	Amplitude identifier
commid	int	Comment identifier
auth	char(15)	Source/originator
subsource	char(8)	Subsystem source
weight	float	Magnitude weight
in_wgt	float	Input weight
mag	float	Magnitude for this station reading
magres	float	Magnitude residual
magcorr	float	Magnitude correction for this station
importance	float	Importance of amplitude
rflag	char	Human/automatic/finalized observation
lddate	date	Load date

Remark Comments
Attribute	Type	Description
commid	int	Comment identifier
lineno	int	Comment line number
remark	char(80)	Free format comment
lddate	date	Load date

Mec Summary information on a moment tensor
Attribute	Type	Description
mecid	int	Mechanism identifier
oridin	int	Origin identifier (input)
oridout	int	Origin identifier (output)
magid	int	Mw magnitude identifier
commid	int	Comment identifier
mechtype	char(2)	Mechanism/moment type
mecalgo	char(15)	Mechanism algorithm
scalar	float	Scalar moment
erscalar	float	Error in scalar moment
tft	char(8)	Time function type
tfd	float	Time function duration
mxx	float	m_xx
myy	float	m_yy
mzz	float	m_zz
mxy	float	m_xy
mxz	float	m_xz
myz	float	m_yz
smxx	float	Uncertainty in m_xx
smyy	float	Uncertainty in m_yy
smzz	float	Uncertainty in m_zz
smxy	float	Uncertainty in m_xy
smxz	float	Uncertainty in m_xz
smyz	float	Uncertainty in m_yz
srcduration	float	Source half-duration
auth	char(15)	Source/origin
subsource	char(8)	Subsystem source
strike1	int	Strike 1 of best double couple
dip1	int	Dip 1 of best double couple
rake1	int	Rake 1 of best double couple
strike2	int	Strike 2 of best double couple
dip2	int	Dip 2 of best double couple
rake2	int	Rake 2 of best double couple
unstrike1	float	Uncertainty in strike 1
undip1	float	Uncertainty in dip 1
unrake1	float	Uncertainty in rake 1
unstrike2	float	Uncertainty in strike 2
undip2	float	Uncertainty in dip 2
unrake2	float	Uncertainty in rake 2
eigenp	float	Eigen pressure
plungep	int	Plunge pressure
strikep	int	Strike pressure
eigenn	float	Eigen null
plungen	int	Plunge null
striken	int	Strike null
eigent	float	Eigen tension
plunget	int	Plunge tension
striket	int	Strike tension
nsta	int	Number of stations used in solution
pvr	int	Percent variance reduction
quality	float	Quality
pdc	int	Percent double couple
pclvd	int	Percent compensated linear vector dipole
piso	int	Percent isotropic
datetime	float	Date solution created
rflag	char	Human/automatic/finalized observation
lddate	date	Load date

Coda Summary information on a coda
Attribute	Type	Description
coid	int	Coda identifier
commid	int	Comment identifier
sta	char(6)	Station code
net	char(8)	Network code
auth	char(15)	Source/originator
subsource	char(8)	Subsystem source
channel	char(3)	Channel name
channelsrc	char(8)	Source of channel name
seedchan	char(3)	SEED channel name
location	char(2)	SEED location
codatype	char(3)	Coda type
afix	float	Nominal coda amplitude
afree	float	Free amplitude
qfix	float	Fixed coda decay constant
qfree	float	Free decay
tau	float	Coda duration (F-P time)
nsample	int	Number of code sample windows
rms	float	Residual of mean squares for coda fit
durtype	char(3)	Duration type
iphase	char(8)	Reported phase
eramp	float	Error in amplitude
units	char(4)	Units of amplitude
time1	int	Time for pair 1
amp1	int	Amplitude for pair 1
time2	int	Time for pair 2
amp2	int	Amplitude for pair 2
time3	int	Time for pair 3
amp3	int	Amplitude for pair 3
time4	int	Time for pair 4
amp4	int	Amplitude for pair 4
time5	int	Time for pair 5
amp5	int	Amplitude for pair 5
time6	int	Time for pair 6
amp6	int	Amplitude for pair 6
quality	float	Subjective quality
datetime	float	Time of coda onset
algorithm	char(15)	Algorithm deriving coda data
winsize	float	Window size
rflag	char	Human/automatic/finalized observation
lddate	date	Load date

AssocCoM Data associating codas with magnitudes
Attribute	Type	Description
magid	int	Magnitude identifier
coid	int	Coda identifier
commid	int	Comment identifier
auth	char(15)	Source/originator
subsource	char(8)	Subsystem source
weight	float	Magnitude weight
in_wgt	float	Input weight
mag	float	Event magnitude determined from coda
magres	float	Magnitude residual
magcorr	float	Magnitude correction
rflag	char	Human/automatic/finalized observation
lddate	date	Load date

AssocCoO Data associating codas with origins
Attribute	Type	Description
orid	int	Origin identifier
coid	int	Coda identifier
commid	int	Comment identifier
auth	char(15)	Source/originator
subsource	char(8)	Subsystem source
delta	float	Distance from the source to the site
seaz	float	Azimuth from the site to source
rflag	char	Human/automatic/finalized observation
lddate	date	Load date