gov.usgs.earthquake.nshmp.eq

Class Earthquakes

java.lang.Object

gov.usgs.earthquake.nshmp.eq.Earthquakes

public final class Earthquakes
extends Object

Constants and utility methods pertaining to properties of earthquakes.

Note: The various fields and methods of this class that relate to earthquake depths follow the positive-down convention of seismology.

Author:

Peter Powers

Field Summary

Fields

Modifier and Type	Field and Description
static Range<Double>	CRUSTAL_DEPTH_RANGE Supported crustal earthquake depths: [0..40] km.
static Range<Double>	CRUSTAL_WIDTH_RANGE Supported crustal earthquake widths: (0..60] km.
static Range<Double>	DEPTH_RANGE Supported earthquake depths: [-5..700] km.
static Range<Double>	INTERFACE_DEPTH_RANGE Supported subduction interface earthquake depths: [0..60] km.
static Range<Double>	INTERFACE_WIDTH_RANGE Supported subduction interface earthquake widths: (0..200] km.
static Range<Double>	MAG_RANGE Supported earthquake magnitudes: [-2.0..9.7].
static double	MU Shear modulus μ = 3·10¹⁰ N·m⁻².
static Range<Double>	SLAB_DEPTH_RANGE Supported subduction intraslab earthquake depths: [20..700] km.

Method Summary

Modifier and Type	Method and Description
static double	checkCrustalDepth(double depth) Ensure 0 ≤ depth ≤ 40 km.
static double	checkCrustalWidth(double width) Ensure 0 < width ≤ 60 km.
static double	checkDepth(double depth) Ensure -5 ≤ depth ≤ 700 km.
static double	checkInterfaceDepth(double depth) Ensure 0 ≤ depth ≤ 60 km.
static double	checkInterfaceWidth(double width) Ensure 0 < width ≤ 200 km.
static double	checkMagnitude(double magnitude) Ensure -2.0 ≤ magnitude ≤ 9.7.
static double	checkSlabDepth(double depth) Ensure 20 ≤ depth ≤ 700 km.
static double	magToMoment(double magnitude) Convert moment magnitude, MW, to seismic moment, M₀, following the equation of Hanks and Kanamori (1997).
static double	moment(double area, double slip) Calculate (in SI units) the seismic moment of a fault area and average slip, assuming a shear modulus of MU.
static double	momentToMag(double moment) Convert seismic moment, M₀, to moment magnitude, Mw, following the equation of Hanks and Kanamori (1997).
static double	slip(double area, double moment) Calculate (in SI units) the average slip across a fault area with the supplied moment, assuming a shear modulus of MU.

Methods inherited from class java.lang.Object

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

Field Detail

DEPTH_RANGE

public static final Range<Double> DEPTH_RANGE

Supported earthquake depths: [-5..700] km.

CRUSTAL_DEPTH_RANGE

public static final Range<Double> CRUSTAL_DEPTH_RANGE

Supported crustal earthquake depths: [0..40] km.

CRUSTAL_WIDTH_RANGE

public static final Range<Double> CRUSTAL_WIDTH_RANGE

Supported crustal earthquake widths: (0..60] km.

INTERFACE_DEPTH_RANGE

public static final Range<Double> INTERFACE_DEPTH_RANGE

Supported subduction interface earthquake depths: [0..60] km.

INTERFACE_WIDTH_RANGE

public static final Range<Double> INTERFACE_WIDTH_RANGE

Supported subduction interface earthquake widths: (0..200] km.

SLAB_DEPTH_RANGE

public static final Range<Double> SLAB_DEPTH_RANGE

Supported subduction intraslab earthquake depths: [20..700] km.

MAG_RANGE

public static final Range<Double> MAG_RANGE

Supported earthquake magnitudes: [-2.0..9.7]. This range of values is not bound to any particular magnitude scale.

MU

public static final double MU

Shear modulus μ = 3·10¹⁰ N·m⁻².

See Also:

Constant Field Values

Method Detail

checkDepth

public static double checkDepth(double depth)

Ensure -5 ≤ depth ≤ 700 km.

Parameters:

depth - to validate

Returns:

the validated depth

Throws:

IllegalArgumentException - if depth is outside the range [-5..700] km

See Also:

DEPTH_RANGE

checkCrustalDepth

public static double checkCrustalDepth(double depth)

Ensure 0 ≤ depth ≤ 40 km.

Parameters:

depth - to validate

Returns:

the validated depth for use inline

Throws:

IllegalArgumentException - if depth is outside the range [0..40] km

See Also:

CRUSTAL_DEPTH_RANGE

checkCrustalWidth

public static double checkCrustalWidth(double width)

Ensure 0 < width ≤ 60 km.

Parameters:

width - to validate

Returns:

the validated width

Throws:

IllegalArgumentException - if width is outside the range (0..60] km

See Also:

CRUSTAL_WIDTH_RANGE

checkInterfaceDepth

public static double checkInterfaceDepth(double depth)

Ensure 0 ≤ depth ≤ 60 km.

Parameters:

depth - to validate

Returns:

the validated depth

Throws:

IllegalArgumentException - if depth is outside the range [0..60] km

See Also:

INTERFACE_DEPTH_RANGE

checkInterfaceWidth

public static double checkInterfaceWidth(double width)

Ensure 0 < width ≤ 200 km.

Parameters:

width - to validate

Returns:

the validated width

Throws:

IllegalArgumentException - if width is outside the range (0..200] km

See Also:

INTERFACE_WIDTH_RANGE

checkSlabDepth

public static double checkSlabDepth(double depth)

Ensure 20 ≤ depth ≤ 700 km.

Parameters:

depth - to validate

Returns:

the validated depth

Throws:

IllegalArgumentException - if depth is outside the range [20..700] km

See Also:

SLAB_DEPTH_RANGE

checkMagnitude

public static double checkMagnitude(double magnitude)

Ensure -2.0 ≤ magnitude ≤ 9.7.

Parameters:

magnitude - to validate

Returns:

the validated magnitude

Throws:

IllegalArgumentException - if magnitude value is outside the range [-2.0..9.7]

See Also:

MAG_RANGE

magToMoment

public static double magToMoment(double magnitude)

Convert moment magnitude, M_W, to seismic moment, M₀, following the equation of Hanks and Kanamori (1997).

Parameters:

magnitude - to convert

Returns:

the equivalent seismic moment in N·m

momentToMag

public static double momentToMag(double moment)

Convert seismic moment, M₀, to moment magnitude, M_w, following the equation of Hanks and Kanamori (1997).

Parameters:

moment - to convert (in N·m)

Returns:

the equivalent moment magnitude

moment

public static double moment(double area,
                            double slip)

Calculate (in SI units) the seismic moment of a fault area and average slip, assuming a shear modulus of MU. If slip rate is supplied, moment rate is returned.

Parameters:

area - in m²

slip - in m (or slip rate in m·t⁻¹)

Returns:

moment (M₀) in N·m (or moment rate in N·m·t⁻¹)

slip

public static double slip(double area,
                          double moment)

Calculate (in SI units) the average slip across a fault area with the supplied moment, assuming a shear modulus of MU. If moment rate is supplied, slip rate is returned.

Parameters:

area - in m²

moment - M₀ in N·m (or moment rate in N·m·t⁻¹)

Returns:

slip in m (or slip rate in m·t⁻¹)