Source code for openquake.hmtk.seismicity.declusterer.distance_time_windows

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4

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"""
"""

import abc
import numpy as np
from openquake.baselib.general import CallableDict

TIME_DISTANCE_WINDOW_FUNCTIONS = CallableDict()
DAYS = 364.75


[docs]def time_window_cutoff(sw_time, time_cutoff): """ Allows for cutting the declustering time window at a specific time, outside of which an event of any magnitude is no longer identified as a cluster """ sw_time = np.array( [ (time_cutoff / DAYS) if x > (time_cutoff / DAYS) else x for x in sw_time ] ) return sw_time
[docs]class BaseDistanceTimeWindow(object): """ Defines the space and time windows, within which an event is identified as a cluster. """
[docs] @abc.abstractmethod def calc(self, magnitude, time_cutoff=None): """ Allows to calculate distance and time windows (sw_space, sw_time) see reference: `Van Stiphout et al (2011)`. :param magnitude: magnitude :type magnitude: numpy.ndarray :param time_cutoff: time window cutoff in days (optional) :type time_cutoff: int :returns: distance and time windows :rtype: numpy.ndarray """ return
[docs]@TIME_DISTANCE_WINDOW_FUNCTIONS.add("GardnerKnopoff") class GardnerKnopoffWindow(BaseDistanceTimeWindow): """ Gardner Knopoff method for calculating distance and time windows """
[docs] def calc(self, magnitude, time_cutoff=None): sw_space = np.power(10.0, 0.1238 * magnitude + 0.983) sw_time = np.power(10.0, 0.032 * magnitude + 2.7389) / DAYS sw_time[magnitude < 6.5] = ( np.power(10.0, 0.5409 * magnitude[magnitude < 6.5] - 0.547) / DAYS ) if time_cutoff: sw_time = time_window_cutoff(sw_time, time_cutoff) return sw_space, sw_time
[docs]@TIME_DISTANCE_WINDOW_FUNCTIONS.add("Gruenthal") class GruenthalWindow(BaseDistanceTimeWindow): """ Gruenthal method for calculating distance and time windows """
[docs] def calc(self, magnitude, time_cutoff=None): sw_space = np.exp(1.77 + np.sqrt(0.037 + 1.02 * magnitude)) sw_time = np.abs( (np.exp(-3.95 + np.sqrt(0.62 + 17.32 * magnitude))) / DAYS ) sw_time[magnitude >= 6.5] = ( np.power(10, 2.8 + 0.024 * magnitude[magnitude >= 6.5]) / DAYS ) if time_cutoff: sw_time = time_window_cutoff(sw_time, time_cutoff) return sw_space, sw_time
[docs]@TIME_DISTANCE_WINDOW_FUNCTIONS.add("UrhammerWindow") class UhrhammerWindow(BaseDistanceTimeWindow): """ Uhrhammer method for calculating distance and time windows """
[docs] def calc(self, magnitude, time_cutoff=None): sw_space = np.exp(-1.024 + 0.804 * magnitude) sw_time = np.exp(-2.87 + 1.235 * magnitude) / DAYS if time_cutoff: sw_time = time_window_cutoff(sw_time, time_cutoff) return sw_space, sw_time