Source code for openquake.hmtk.faults.fault_geometries

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

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# LICENSE
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# Copyright (c) 2010-2017, GEM Foundation, G. Weatherill, M. Pagani,
# D. Monelli.
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# The software Hazard Modeller's Toolkit (openquake.hmtk) provided herein
#is released as a prototype implementation on behalf of
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#Earthquake Model).
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# hope that it will be useful to the scientific, engineering, disaster
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# developers, as GEM's OpenQuake software suite.
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import abc
import numpy as np
from openquake.hazardlib.geo.surface.simple_fault import SimpleFaultSurface
from openquake.hazardlib.geo.surface.complex_fault import ComplexFaultSurface


class BaseFaultGeometry(object):
    '''
    Abstract base class to support geometry parameters and methods
    '''
    __metaclass__ = abc.ABCMeta

    @abc.abstractmethod
    def get_area(self):
        '''
        Returns the area of the fault surface
        '''


class SimpleFaultGeometry(BaseFaultGeometry):
    '''
    Describes the geometrical propeties of a simple fault surface

    :param str typology:
        Source typology
    :param trace:
        Fault trace as instance of :class: openquake.hazardlib.geo.line.Line
    :param float dip:
        Fault dip (degrees)
    :param float upper_depth:
        Upper seismogenic depth (km)
    :param float lower_depth:
        Lower seismogenic depth (km)
    :param surface:
        Instance of
        :class: openquake.hazardlib.geo.surface.simple_fault.SimpleFaultSurface
    :param float length:
        Along-strike length of fault (km)
    :param float width:
        Down-dip width of fault (km)
    :param float area:
        Length of fault (km)

    '''
    def __init__(self, trace, dip, upper_depth, lower_depth, mesh_spacing=1.0):
        '''
        Sets up the fault geometry parameters from the input fault definitions
        :param float mesh_spacing:
            Spacing (km) of the fault surface mesh
        '''
        self.typology = 'Simple'
        self.trace = trace
        self.dip = dip
        self.upper_depth = upper_depth
        self.lower_depth = lower_depth
        self.surface = SimpleFaultSurface.from_fault_data(self.trace,
                                                          self.upper_depth,
                                                          self.lower_depth,
                                                          self.dip,
                                                          mesh_spacing)
        self.length = trace.get_length()
        self.downdip_width = None
        self.surface_width = None
        self.area = None

    def get_area(self):
        '''
        Calculates the area of the fault (km ** 2.) as the product of length
        (km) and downdip width (km)
        '''
        d_z = self.lower_depth - self.upper_depth
        self.downdip_width = d_z / np.sin(self.dip * np.pi / 180.)
        self.surface_width = self.downdip_width * np.cos(self.dip *
                                                         np.pi / 180.)
        self.area = self.length * self.downdip_width
        return self.area


class ComplexFaultGeometry(BaseFaultGeometry):
    '''
    Module openquake.hmtk.faults.fault_model.ComplexFaultGeometry describes the
    geometrical properties of a complex fault surface

    :param str typology:
        Source typology
    :param trace:
        Fault edges as list of instances of :class:
        openquake.hazardlib.geo.line.Line
    :param float dip:
        Fault dip (degrees)
    :param float upper_depth:
        Upper seismogenic depth (km)
    :param float lower_depth:
        Lower seismogenic depth (km)
    :param surface:
        Instance of :class:
        openquake.hazardlib.geo.surface.complex_fault.ComplexFaultSurface
    :param float length:
        Along-strike length of fault (km)
    :param float width:
        Down-dip width of fault (km)
    :param float area:
        Length of fault (km)
    '''
    def __init__(self, traces, mesh_spacing=1.0):
        '''
        Set up function an creates complex fault surface
        :param list traces:
            Edges of the complex fault as a list of :class:
            openquake.hazardlib.geo.line.Line. Please refer to documentation of
            openquake.hazardlib.geo.surface.complex_fault.ComplexFaultSurface
            for details.
        :param float mesh_spacing:
            Spacing (km) of the fault surface mesh
        '''
        self.typology = 'Complex'
        self.trace = traces
        self.upper_depth = None
        self.lower_depth = None
        self.surface = ComplexFaultSurface.from_fault_data(self.trace,
                                                           mesh_spacing)
        self.dip = self.surface.get_dip()

    def get_area(self):
        '''
        Calculates the area of the complex fault from the surface mesh uses
        :class: openquake.hazardlib.surface.complex_fault.ComplexFaultSurface
        '''
        return self.surface.get_area()