GraviLab

Package to analyze seismic data based on obspy and spicypy packages.

Installation

pip install gravilab

Usage

The main element of the package is Seismometer class, which represents a seismic instrument. It can be created by loading seismic data with open function and specifying channels, both their names in the file and "human-readable" names. The folder is then scanned for any suitable data and only those channels are loaded. All functionality related to seismic time series data is provided by the underlying obspy package (specifically obspy.Trace).

Seismometer class also supports calculating spectrum (Seismometer.asd(), Seismometer.psd()) using spicypy package. Spectrum can be adjusted by the response of specific instrument specified by pole-zero model, and units can be converted between displacement, velocity and acceleration by specifying the omega factor. Resulting spectrum is spicypy.FrequencySeries. Additionally, time series can also be converted to spicypy.TimeSeries to profit from its rich signal processing functionality.

Minimal example:

import gravilab as gl
Seismometer1 = gl.open("seismic", channels = {"vertical":"HNZ","north":"HNY","east":"HNX"}, name="seismometer1")
Seismometer1.time_series["north"].plot()
response = {"poles" : [-0.036614 +0.037059j, -0.036614 -0.037059j, -32.55, -142, -364 +404j, -364 -404j, -1260, -4900 +5200j, -4900 -5200j, -7100 +1700j, -7100 -1700j],
            "zeros" : [0, 0, -31.63, -160, -350, -3177],
            "scale_factor" : 1202.5 * 8.31871e17 * 400000, #V/(m/s) times gain times counts/V
            "omega_exponent": -1, #convert from m/s to m
           }
Seismometer1.response = response
Seismometer1.asd()["north"].plot()

More detailed usage examples are provided in gravilab/examples folder.