gov.usgs.earthquake.nshmp.eq.fault

Class Faults

java.lang.Object

gov.usgs.earthquake.nshmp.eq.fault.Faults

public final class Faults
extends Object

Constants and utility methods pertaining to faults.

Author:

Peter Powers

Field Summary

Fields

Modifier and Type	Field and Description
static Range<Double>	DIP_RANGE Supported fault dips: [0..90]°.
static Range<Double>	RAKE_RANGE Supported fault rakes: [-180..180]°.
static Range<Double>	STRIKE_RANGE Supported fault strikes: [0..360)°.

Method Summary

Modifier and Type	Method and Description
static double	checkDip(double dip) Ensure 0° ≤ dip ≤ 90°.
static double	checkRake(double rake) Ensure -180° ≤ rake ≤ 180°.
static double	checkStrike(double strike) Ensure 0° ≤ strike < 360°.
static LocationList	checkTrace(LocationList trace) Ensure trace contains at least two points.
static double	dipDirection(double strike)
static double	dipDirection(LocationList locs) Returns the dip direction for the supplied line/trace assuming the right-hand rule (strike + 90°).
static double	dipDirection(Location p1, Location p2)
static double	dipDirectionRad(double strikeRad)
static double	dipDirectionRad(LocationList locs)
static double	dipDirectionRad(Location p1, Location p2)
static double	getAngleAverage(List<Double> angles) Averages angles dealing with any -180/180 or 0/360 cut issues.
static List<LocationList>	getEqualLengthSubsectionTraces(LocationList faultTrace, double maxSubSectionLen) This subdivides the given fault trace into sub-traces that have the length as given (or less).
static List<LocationList>	getEqualLengthSubsectionTraces(LocationList faultTrace, double maxSubSectionLen, int minSubSections) This subdivides the given fault trace into sub-traces that have the length as given (or less).
static double	getLengthBasedAngleAverage(LocationList locs, List<Double> angles) Returns an average of the given angles scaled by the distances between the corresponding locations.
static double	getScaledAngleAverage(List<Double> scalars, List<Double> angles) Returns an average of the given angles scaled by the given scalars.
static double[]	getSlipVector(double[] strikeDipRake) Calculates a slip vector from strike, dip, and rake information provided.
static double	hypocentralDepth(double dip, double width, double zTop) Generic model for hypocentral depth returns a value that is halfway between the top and bottom of a fault, parameterized by its dip, width, and depth.
static LocationList	resampleTrace(LocationList trace, int num) This resamples the trace into num subsections of equal length (final number of points in trace is num+1).
static double	strike(LocationList locs) Compute the strike in degrees of the supplied line, or trace, by connecting the first and last points in locs.
static double	strike(Location p1, Location p2) Compute the strike in degrees of the line connecting p1 to p2.
static double	strikeRad(LocationList locs) Compute the strike in radians of the supplied line, or trace, by connecting the first and last points in locs.
static double	strikeRad(Location p1, Location p2) Compute the strike in degrees of the line connecting p1 to p2.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DIP_RANGE

public static final Range<Double> DIP_RANGE

Supported fault dips: [0..90]°.

RAKE_RANGE

public static final Range<Double> RAKE_RANGE

Supported fault rakes: [-180..180]°.

STRIKE_RANGE

public static final Range<Double> STRIKE_RANGE

Supported fault strikes: [0..360)°.

Method Detail

checkDip

public static double checkDip(double dip)

Ensure 0° ≤ dip ≤ 90°.

Parameters:

dip - to validate

Returns:

the validated dip

Throws:

IllegalArgumentException - if dip is outside the range [0..90]°

checkStrike

public static double checkStrike(double strike)

Ensure 0° ≤ strike < 360°.

Parameters:

strike - to validate

Returns:

the validated strike

Throws:

IllegalArgumentException - if strike is outside the range [0..360)°

checkRake

public static double checkRake(double rake)

Ensure -180° ≤ rake ≤ 180°.

Parameters:

rake - to validate

Returns:

the validated rake

Throws:

IllegalArgumentException - if rake is outside the range [-180..180]°

checkTrace

public static LocationList checkTrace(LocationList trace)

Ensure trace contains at least two points.

Parameters:

trace - to validate

Returns:

the validated trace

Throws:

IllegalArgumentException - if trace.size() < 2

getEqualLengthSubsectionTraces

public static List<LocationList> getEqualLengthSubsectionTraces(LocationList faultTrace,
                                                                double maxSubSectionLen)

This subdivides the given fault trace into sub-traces that have the length as given (or less). This assumes all fault trace points are at the same depth.

Parameters:

faultTrace -

maxSubSectionLen - Maximum length of each subsection

Returns:

a List of subsection traces

getEqualLengthSubsectionTraces

public static List<LocationList> getEqualLengthSubsectionTraces(LocationList faultTrace,
                                                                double maxSubSectionLen,
                                                                int minSubSections)

This subdivides the given fault trace into sub-traces that have the length as given (or less). This assumes all fault trace points are at the same depth.

Parameters:

faultTrace -

maxSubSectionLen - Maximum length of each subsection

minSubSections - minimum number of sub sections to generate

Returns:

a List of subsection traces

resampleTrace

public static LocationList resampleTrace(LocationList trace,
                                         int num)

This resamples the trace into num subsections of equal length (final number of points in trace is num+1). However, note that these subsections of are equal length on the original trace, and that the final subsections will be less than that if there is curvature in the original between the points (e.g., corners getting cut).

Parameters:

trace -

num - - number of subsections

getLengthBasedAngleAverage

public static double getLengthBasedAngleAverage(LocationList locs,
                                                List<Double> angles)

Returns an average of the given angles scaled by the distances between the corresponding locations. Note that this expects angles in degrees, and will return angles from 0 to 360 degrees.

Parameters:

locs - locations for distance scaling

angles - angles in degrees corresponding to each pair of locations

getScaledAngleAverage

public static double getScaledAngleAverage(List<Double> scalars,
                                           List<Double> angles)

Returns an average of the given angles scaled by the given scalars. Note that this expects angles in degrees, and will return angles from 0 to 360 degrees.

Parameters:

scalars - scalar weights for each angle (does not need to be normalized)

angles - angles in degrees corresponding to each pair of locations

getAngleAverage

public static double getAngleAverage(List<Double> angles)

Averages angles dealing with any -180/180 or 0/360 cut issues. Note that this expects angles in degrees, and will return angles from 0 to 360 degrees.

Parameters:

angles -

hypocentralDepth

public static double hypocentralDepth(double dip,
                                      double width,
                                      double zTop)

Generic model for hypocentral depth returns a value that is halfway between the top and bottom of a fault, parameterized by its dip, width, and depth. This method performs no input validation.

Parameters:

dip - of the fault plane

width - of the fault plane

zTop - depth to the fault plane

strike

public static double strike(LocationList locs)

Compute the strike in degrees of the supplied line, or trace, by connecting the first and last points in locs. Method forwards to Locations.azimuth(Location, Location).

This approach has been shown to be as accurate as length-weighted angle averaging and is significantly faster; see StrikeDirectionMethods for more information.

Parameters:

locs - line for which to compute strike

Returns:

strike direction in the range [0°, 360°)

See Also:

strikeRad(LocationList)

strike

public static double strike(Location p1,
                            Location p2)

Compute the strike in degrees of the line connecting p1 to p2.

Parameters:

p1 - starting Location

p2 - ending Location

Returns:

strike direction in the range [0°, 360°)

See Also:

strikeRad(Location, Location)

strikeRad

public static double strikeRad(LocationList locs)

Compute the strike in radians of the supplied line, or trace, by connecting the first and last points in locs. Method forwards to Locations.azimuth(Location, Location).

This approach has been shown to be as accurate as length-weighted angle averaging and is significantly faster; see StrikeDirectionMethods for more information.

Parameters:

locs - line for which to compute strike

Returns:

strike direction in the range [0, 2π)

See Also:

strike(LocationList)

strikeRad

public static double strikeRad(Location p1,
                               Location p2)

Compute the strike in degrees of the line connecting p1 to p2.

Parameters:

p1 - starting Location

p2 - ending Location

Returns:

strike direction in the range [0, 2π)

See Also:

strike(Location, Location)

dipDirection

public static double dipDirection(LocationList locs)

Returns the dip direction for the supplied line/trace assuming the right-hand rule (strike + 90°).

Parameters:

locs - line for which to compute dip direction

Returns:

dip direction in the range 0° and 360°)

dipDirectionRad

public static double dipDirectionRad(LocationList locs)

dipDirection

public static double dipDirection(Location p1,
                                  Location p2)

dipDirectionRad

public static double dipDirectionRad(Location p1,
                                     Location p2)

dipDirection

public static double dipDirection(double strike)

dipDirectionRad

public static double dipDirectionRad(double strikeRad)

getSlipVector

public static double[] getSlipVector(double[] strikeDipRake)

Calculates a slip vector from strike, dip, and rake information provided.

Parameters:

strikeDipRake - array

Returns:

double[x,y,z] array for slip vector.