POST /finite_source

Note

Some parts of this route require an advanced server setup. Please view the Advanced Server Configuration for details. The parts that don’t will keep working even with a normal configuration.

Per default this route allows at most 1000 point sources for a single finite source. This limit can be changed when starting the server.

Description
Returns seismograms for finite sources defined in the USGS param file format. Just POST the file and set additional parameters in the URL.
What is Actually Happening

Some of the calculations performed in this endpoint are not immediatly obvious and some choices have to be made so we’ll elaborate a bit here.

  1. The sliprate of each point source is defined as an asymmetric cosine with a certain rupture, rise, and fall time. We sample it at 10 Hz for a thousand seconds - this limits the maximum rise and fall times. Rise and fall times smaller than one second will be set to one second to make sure it can be accurately sampled.
  2. Each sampled sliprate is zero padded with a number of samples at the beginning and the end (the additional time shift is later accounted for). This is done to avoid running into boundary issues with the following filter.
  3. A fourth order Butterworth filter is applied twice (forwards and backwards) resulting in a zero phase filter. The corner frequency is the dominant frequency of the database. This makes sure we don’t introduce frequencies in the convolution that we cannot propagate in the numerical simulation.
  4. The seismograms for all point sources are calculated, time-shifted, convolved, and stacked.
Content-Type
  • application/zip (if zipped SAC data is requested)
  • application/octet-stream (if MiniSEED data is requested)
Filetype

Returns a ZIP archive with SAC files or MiniSEED files encoded with encoding format 4 (IEEE floating point).

SAC files will have the following user defined variables set:

  • KUSER0: “InstSeis”
  • KUSER1: The first eight letters of the used velocity model.
  • KT7: The first seven letters of the AxiSEM version number used to generate the model. Prefixed with A.
  • KT8: The first seven letters of the Instaseis version number used to generate the seismogram. Prefixed with I.
  • USER0: The scale factor used to generate the waveforms.
Parameter Type Required Default Value Description
Output parameters
format String False saczip Specify output file to be either MiniSEED or a ZIP archive of SAC files, either miniseed or saczip.
label String False   Specify a label to be included in file names and HTTP file name suggestions.
components String False ZNE, Z, or NE (depends on what the DB supports) Specify the orientation of the synthetic seismograms as a list of any combination of Z (vertical), N (north), E (east), R (radial), T (transverse).
units String False displacement Specify either displacement, velocity or acceleration for the synthetics.
dt Float False   If given, seismograms will be resampled to the desired sample spacing.
scale Float False 1.0 Scalar factor to multiply the seismograms with.
kernelwidth Integer False 12 Specify the width of the sinc kernel used for resampling to requested sample interval in terms of the original sampling interval.
Time Parameters
origintime Datetime False 1900-01-01T00:00:00.000000Z Specify the source origin time. This must be specified as an absolute date and time. This time conincides will be the onset time of the first slipping point source. USGS param files don’t have absolute time values.
starttime Datetime False  

Specifies the desired start time for the synthetic trace(s). This may be specified as either:

  • an absolute date and time
  • a phase-relative offset
  • an offset from origin time in seconds

If the value is recognized as a date and time, it is interpreted as an absolute time. If the value is in the form phase[+-]offset it is interpreted as a phase-relative time, for example P-10 (meaning P-wave arrival time minus 10 seconds). If the value is a numerical value it is interpreted as an offset, in seconds, from the origin time. Arrival times are always relative to the origin time.

endtime Datetime False  

Specifies the desired end time for the synthetic trace(s). This may be specified as either:

  • an absolute date and time
  • a phase-relative offset
  • an offset (duration) from start time in seconds

If the value is recognized as a date and time, it is interpreted as an absolute time. If the value is in the form phase[+-]offset it is interpreted as a phase-relative time, for example P-10 (meaning P-wave arrival time minus 10 seconds). If the value is a numerical value it is interpreted as an offset, in seconds, from the start time. Arrival times are always relative to the origin time.

Receiver Parameters
Directly specify coordinates and network/station codes …
receiverlatitude Float True   The geocentric latitude of the receiver.
receiverlongitude Float True   The longitude of the receiver.
networkcode String False XX Specify the network code of the final seismograms. Maximum of two letters.
stationcode String False SYN Specify the station code of the final seismograms. Maximum of five letters.
locationcode String False SE Specify the location code of the final seismograms. Maximum of two letters.
… or use wildcard searches over network and station codes. Potentially returns multiple stations.
network String False   Wildcarded network codes, e.g. I*,B?,AU.
station String False   Wildcarded station codes, e.g. A*,ANMO.