`salvus.modules.near_surface.processing.geophone_response`

Functions for computing, removing, and plotting geophone responses.

Functions

`compute_geophone_response()`

def compute_geophone_response(
    frequencies: np.ndarray,
    geophone_frequency: float,
    damping_ratio: float,
    calibration_factor: float,
) -> np.ndarray: ...

Compute the frequency response of a geophone relative to ground velocity.

Assumes a simplified second-order damped spring-mass system that nonetheless should be fairly accurate for many uses.

Parameters

frequencies np.ndarray — Frequencies for which to compute the response in Hz.
geophone_frequency float — The natural frequency of the geophone in Hz.
damping_ratio float — The damping ratio. Between 0 and 1.
calibration_factor float — The calibration factor. Usually given as V/m or V/inch. Make sure the units are correct for your application. Salvus computes everything in SI units.

Returns np.ndarray

`plot_response()`

def plot_response(
    frequencies: np.ndarray,
    response: np.ndarray,
    geophone_frequency: float | None = None,
    fig: matplotlib.figure.Figure | None = None,
    label: str | None = None,
    log_base: int = 2,
) -> matplotlib.figure.Figure: ...

Create a Bode plot of an existing frequency response.

Parameters

frequencies np.ndarray — Array of frequencies in Hz.
response np.ndarray — Array of the complex response. One item for each frequency.
geophone_frequency float | None — Geophone frequency in Hz. If given, a vertical line will be drawn at that frequency.
fig matplotlib.figure.Figure | None — If given, the figure will be used. Useful to plot multiple responses.
label str | None — Label for the response.
log_base int — Base for the logarithmic axes.

Returns matplotlib.figure.Figure

`remove_geophone_response()`

def remove_geophone_response(
    tr: obspy.Trace,
    geophone_frequency: float,
    calibration_factor: float,
    damping_ratio: float,
    frequency_taper: tuple[float, float] | None = None,
) -> obspy.Trace: ...

Remove the geophone response from a given trace and return a new trace object.

Uses the compute_geophone_response() function to compute the actual response.

Parameters

tr obspy.Trace — Trace with the to be corrected data.
geophone_frequency float — The natural frequency of the geophone in Hz.
calibration_factor float — The calibration factor. Usually given as V/m or V/inch. Make sure the units are correct for your application. Salvus computes everything in SI units.
damping_ratio float — The damping ratio. Between 0 and 1.
frequency_taper tuple[float, float] | None — Frequency domain taper (bandpass filter) to stabilize the spectral division. Must be given as a tuple of two values: The min and max frequency of the passband. There will be a transition zone between (min/2 - min) and (max - max * 2.0) to go from stop to passband.

Returns obspy.Trace — A new obspy.Trace object with the geophone response being removed.