Anglais - Français


Webservice ppsd

This service queries a database of hourly segmented power spectral densities (PSDs). Individual PSDs are aggregated to show probabilistic distributions of the seismic noise levels. PSDs are calculated by the method described by McNamara, 2004 using ObsPy for a particular network/station/location/channel combination.

Query usage

/query? (channel-options) (date-range-options) [plot-options] [output-options] [nodata=404]


channel-options      ::  (net=<network>) (sta=<station>) (loc=<location>) (cha=<channel>)
date-range-options   ::  (starttime=<date|duration>) (endtime=<date|duration>)
plot-options         ::  [dpi=<dots per inch>] [width=<pixels>] [height=<pixels>] [coverage=<true|false>] [cumulative=<true|false>] [spectrogram=<true|false>]
output-options       ::  [format=<plot|npz>]

(..) required
[..] optional

Sample queries

Detailed descriptions of each query parameter

Parameter Example Discussion
net[work] FR Seismic network name.
sta[tion] CIEL Station name.
loc[ation] 00 Location code. Use loc=-- for empty location codes.
cha[nnel] HHZ Channel Code.
width 800 Width of the figure. Between 640 and 2000. Defaults to 900.
height 600 Height of the figure. Between 480 and 2000. Defaults to 600.
dpi 150 Resolution of the figure. Defaults to 100.
cumulative true Cumulative version of the histogram.
coverage false Display the data coverage below the PPSD histogram. Only years that are included in the user selection are represented. Green patches represent available data and red patches represent gaps in streams. The bottom row in blue shows psd measurements that are actually present into the histogram whereas gray patches show unselected data.
spectrogram true Plot the temporal evolution of the PSDs in a spectrogram-like plot.
format plot Output format. Must be: plot for the graphical output or npz for the compressed numpy binary format

Date-range options

Parameter Example Discussion
start[time] 2010-01-10T00:00:00 Selects power spectral density on or after the specified start time.
end[time] 2011-02-11T01:00:00 Selects power spectral density on or before the specified end time.

The definition of the time interval may take different forms:

Date and time formats

YYYY-MM-DDThh:mm:ss[.ssssss] ex. 1997-01-31T12:04:32.123
YYYY-MM-DD ex. 1997-01-31 (a time of 00:00:00 is assumed)


YYYY    :: four-digit year
MM      :: two-digit month (01=January, etc.)
DD      :: two-digit day (01 through 31)
T       :: date-time separator
hh      :: two-digit hour (00 through 23)
mm      :: two-digit number of minutes (00 through 59)
ss      :: two-digit number of seconds (00 through 59)
ssssss  :: one to six-digit number of microseconds (0 through 999999)