43 lines
1.0 KiB
Python
43 lines
1.0 KiB
Python
import numpy as np
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# constants depending on source models
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K_BRUNE = 0.37
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K_MADARIAGA_P = 0.32
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K_MADARIAGA_S = 0.21
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# averages of radiation coefficients
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G_P = 0.52
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G_S = 0.63
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def spectrum2moment(spectral_level, density, velocity, distance, g):
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return spectral_level * 4.0 * np.pi * density * velocity ** 3 * distance / g
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def damping(q_factor, frequencies, travel_time):
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"""Exponential damping"""
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return np.exp(np.pi * frequencies * travel_time / q_factor)
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def mm(mo):
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"""Calculate moment magnitude from the spectral level (Mo)
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:return moment magnitude (float):
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"""
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return (np.log10(mo) - 9.1) / 1.5
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def m0(mw):
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"""Calculate the spectral level (Mo) from the moment magnitude (Mw)
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:return spectral level (float):
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"""
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return 10 ** (mw * 1.5 + 9.1)
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def calc_source_size(s_vel, corner_freq, k):
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"""Calculate source radius"""
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return k * s_vel / corner_freq
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def calc_stress_drop(seismic_moment, source_radius):
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"""Calculate stress drop"""
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return 7 / 16 * seismic_moment / source_radius ** 3
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