obspy-data-api

ObsPy Data API

Waveform Data

Summary

Seismograms of various formats (e.g. SAC, MiniSEED, GSE2, SEISAN, Q, etc.) can be imported into a Stream object using the read() function.

Streams are list-like objects which contain multiple Trace objects, i.e. gap-less continuous time series and related header/meta information.

Each Trace object has the attribute data pointing to a NumPy ndarray of the actual time series and the attribute stats which contains all meta information in a dict-like Stats object. Both attributes starttime and endtime of the Stats object are UTCDateTime objects.

A multitude of helper methods are attached to Stream and Trace objects for handling and modifying the waveform data.

Stream and Trace Class Structure

Hierarchy: Stream → Trace (multiple)

Trace - DATA:

• data → NumPy array
• stats:
  • network, station, location, channel — Determine physical location and instrument
  • starttime, sampling_rate, delta, endtime, npts — Interrelated

Trace - METHODS:

• taper() — Tapers the data.
• filter() — Filters the data.
• resample() — Resamples the data in the frequency domain.
• integrate() — Integrates the data with respect to time.
• remove_response() — Deconvolves the instrument response.

Example

A Stream with an example seismogram can be created by calling read() without any arguments. Local files can be read by specifying the filename, files stored on http servers (e.g. at https://examples.obspy.org) can be read by specifying their URL.

>>> from obspy import read
>>> st = read()
>>> print(st)
3 Trace(s) in Stream:
BW.RJOB..EHZ | 2009-08-24T00:20:03.000000Z - ... | 100.0 Hz, 3000 samples
BW.RJOB..EHN | 2009-08-24T00:20:03.000000Z - ... | 100.0 Hz, 3000 samples
BW.RJOB..EHE | 2009-08-24T00:20:03.000000Z - ... | 100.0 Hz, 3000 samples
>>> tr = st[0]
>>> print(tr)
BW.RJOB..EHZ | 2009-08-24T00:20:03.000000Z - ... | 100.0 Hz, 3000 samples
>>> tr.data
array([ 0.        ,  0.00694644,  0.07597424, ...,  1.93449584,
        0.98196204,  0.44196924])
>>> print(tr.stats)
         network: BW
         station: RJOB
        location:
         channel: EHZ
       starttime: 2009-08-24T00:20:03.000000Z
         endtime: 2009-08-24T00:20:32.990000Z
   sampling_rate: 100.0
           delta: 0.01
            npts: 3000
           calib: 1.0
           ...
>>> tr.stats.starttime
UTCDateTime(2009, 8, 24, 0, 20, 3)

Event Metadata

Event metadata are handled in a hierarchy of classes closely modelled after the de-facto standard format QuakeML. See read_events() and Catalog.write() for supported formats.

Event Class Structure

Hierarchy: Catalog → events → Event (multiple)

Event contains:

• origins → Origin (multiple)
  • latitude, longitude, depth, time, ...
• magnitudes → Magnitude (multiple)
  • mag, magnitude_type, ...
• picks
• focal_mechanisms

Station Metadata

Station metadata are handled in a hierarchy of classes closely modelled after the de-facto standard format FDSN StationXML which was developed as a human readable XML replacement for Dataless SEED. See read_inventory() and Inventory.write() for supported formats.

Inventory Class Structure

Hierarchy: Inventory → networks → Network → stations → Station → channels → Channel

Network:

• code, description, ...

Station:

• code, latitude, longitude, elevation, start_date, end_date, ...

Channel:

• code, location_code, latitude, longitude, elevation, depth, dip, azimuth, sample_rate, start_date, end_date, response, ...

Classes & Functions

Class/Function	Description
read	Read waveform files into an ObsPy Stream object.
Stream	List-like object of multiple ObsPy Trace objects.
Trace	An object containing data of a continuous series, such as a seismic trace.
Stats	A container for additional header information of an ObsPy Trace object.
UTCDateTime	A UTC-based datetime object.
read_events	Read event files into an ObsPy Catalog object.
Catalog	Container for Event objects.
Event	Describes a seismic event which does not necessarily need to be a tectonic earthquake.
read_inventory	Function to read inventory files.
Inventory	The root object of the Network → Station → Channel hierarchy.

Modules

Module	Description
obspy.core.trace	Module for handling ObsPy Trace and Stats objects.
obspy.core.stream	Module for handling ObsPy Stream objects.
obspy.core.utcdatetime	Module containing a UTC-based datetime class.
obspy.core.event	Module handling event metadata.
obspy.core.inventory	Module for handling station metadata.
obspy.core.util	Various utilities for ObsPy.
obspy.core.preview	Tools for creating and merging previews.