Intensity measure types

Module openquake.hazardlib.imt defines different intensity measure types.

class openquake.hazardlib.imt.PGA[source]

Peak ground acceleration during an earthquake measured in units of g, times of gravitational acceleration.

class openquake.hazardlib.imt.PGV[source]

Peak ground velocity during an earthquake measured in units of cm/sec.

class openquake.hazardlib.imt.PGD[source]

Peak ground displacement during an earthquake measured in units of cm.

class openquake.hazardlib.imt.SA[source]

Spectral acceleration, defined as the maximum acceleration of a damped, single-degree-of-freedom harmonic oscillator. Units are g, times of gravitational acceleration.

Parameters:
  • period – The natural period of the oscillator in seconds.
  • damping – The degree of damping for the oscillator in percents.
Raises:

ValueError – if period or damping is not positive.

damping

itemgetter(item, ...) –> itemgetter object

Return a callable object that fetches the given item(s) from its operand. After f = itemgetter(2), the call f(r) returns r[2]. After g = itemgetter(2, 5, 3), the call g(r) returns (r[2], r[5], r[3])

period

itemgetter(item, ...) –> itemgetter object

Return a callable object that fetches the given item(s) from its operand. After f = itemgetter(2), the call f(r) returns r[2]. After g = itemgetter(2, 5, 3), the call g(r) returns (r[2], r[5], r[3])

class openquake.hazardlib.imt.IA[source]

Arias intensity. Determines the intensity of shaking by measuring the acceleration of transient seismic waves. Units are m/s.

class openquake.hazardlib.imt.CAV[source]

Cumulative Absolute Velocity. Defins the integral of the absolute acceleration time series. Units are “g-sec”

class openquake.hazardlib.imt.RSD[source]

Relative significant duration, 5-95% of Arias intensity, in seconds.

class openquake.hazardlib.imt.MMI[source]

Modified Mercalli intensity, a Roman numeral describing the severity of an earthquake in terms of its effects on the earth’s surface and on humans and their structures.