Raghukanth & Iyengar 2007¶

class
openquake.hazardlib.gsim.raghukanth_iyengar_2007.
RaghukanthIyengar2007
[source]¶ Implements GMPE of Raghukanth & Iyengar (2007) for stable continental regions of peninsular India.
This model is intended to be used to predict ground motions in peninsular India, a stable continental region with nonetheless significant seismic hazard (see Section 1 “Introduction”, p. 199 and Section 2 “Seismological model”, p. 200)
Page number citations in this documentation refer to:
Raghukanth, S. and Iyengar, R. (2007). Estimation of seismic spectral acceleration in peninsular India. Journal of Earth System Science, 116(3):199–214.

COEFFS_BEDROCK
= <openquake.hazardlib.gsim.base.CoeffsTable object>¶ Coefficients taken from Table 3, p. 205.

COEFFS_NEHRP
= {'A': <openquake.hazardlib.gsim.base.CoeffsTable object at 0x2ac4c210edd0>, 'C': <openquake.hazardlib.gsim.base.CoeffsTable object at 0x2ac4c210e8d0>, 'B': <openquake.hazardlib.gsim.base.CoeffsTable object at 0x2ac4c210e490>, 'D': <openquake.hazardlib.gsim.base.CoeffsTable object at 0x2ac4c210efd0>}¶ Site class coefficients taken from Table 5, p. 208.

DEFINED_FOR_INTENSITY_MEASURE_COMPONENT
= 'Average horizontal'¶ This is not clear in the paper, but Figure 7 shows the model “compared with the average of the response spectrum of the two horizontal components” of a particular recording.
AVERAGE_HORIZONTAL
, see p. 211.

DEFINED_FOR_INTENSITY_MEASURE_TYPES
= set([<class 'openquake.hazardlib.imt.PGA'>, <class 'openquake.hazardlib.imt.SA'>])¶ Set of
intensity measure types
this GSIM can calculate. A set should contain classes from moduleopenquake.hazardlib.imt
.

DEFINED_FOR_STANDARD_DEVIATION_TYPES
= set(['Total'])¶ Although “the coefficients of [equation (1)] are obtained from the simulated database of SA by a twostep stratified regression following Joyner and Boore (1981)” (p. 203), the standard deviations of the intermediate steps are not reported, so only total standard deviation is supported.

DEFINED_FOR_TECTONIC_REGION_TYPE
= 'Stable Shallow Crust'¶ Supported tectonic region type is ‘stable continental’ since peninsular India “is similar to many other stable continental regions (SCR) of the world” (p. 200).

REQUIRES_DISTANCES
= set(['rhypo'])¶ Required distance measure is hypocentral distance, see p. 203.

REQUIRES_RUPTURE_PARAMETERS
= set(['mag'])¶ Sole required rupture parameter is magnitude, since faulting style is not addressed.

REQUIRES_SITES_PARAMETERS
= set(['vs30'])¶ Required site parameter Vs30 is used to determing the NEHRP site class, and thus to choose site amplification coefficients and site amplification stanard error from Table 5 on p. 208.

get_mean_and_stddevs
(sites, rup, dists, imt, stddev_types)[source]¶ See
superclass method
for specification of input and result values.Implements the following equations:
Equation (8) on p. 203 for the bedrock ground motion:
ln(y_br) = c1 + c2*(M  6) + c3*(M  6)**2  lnR  c4*R + ln(ε_br)
Equation (9) on p. 207 gives the site amplification factor:
ln(F_s) = a1*y_br + a2 + ln(δ_site)
Equation (10) on p. 207 for the ground motion at a given site:
y_site = y_br*F_s
Equation (11) on p. 207 for total standard error at a given site:
σ{ln(ε_site)} = sqrt(σ{ln(ε_br)}**2 + σ{ln(δ_site)}**2)

get_nehrp_classes
(sites)[source]¶ Site classification threshholds from Section 4 “Site correction coefficients” p. 205. Note that site classes E and F are not supported.

is_bedrock
(sites)[source]¶ A threshhold is not explicitly defined but the intention can be inferred from the statement that “The above results are valid at the bedrock level, with Vs nearly equal to 3.6 km/s.” p. 203

non_verified
= True¶ Verification of mean value data was done by digitizing Figures 3 and 5 using http://arohatgi.info/WebPlotDigitizer/ app/. Maximum error was relatively high, approximately 10%, but could be reduced to approximately 1.5% by making the following changes to what may be typographical errors in the published coefficients. In each case the value sugstituted is interpolated from neighbouring values.
RaghukanthIyengar2007 COEFFS_BEDROCK (Table 3) at 1.200 s:
 change c1 from 0.2904 to 0.1904
RaghukanthIyengar2007 COEFFS_NEHRP_C (Table 5) at 0.750 s:
 change a1 from 0.36 to 0.30
RaghukanthIyengar2007Southern COEFFS_BEDROCK (Table 2(b)) at 2.000 s:
 change c4 from 0.0001 to 0.0010
Note that these would be in addition to the following more obvious correction which was implemented.
RaghukanthIyengar2007Southern COEFFS_BEDROCK (Table 2(b)) at 0.150 s:
 change c1 from .1941 to 2.1941
Note that since test data was dervied from Figures 3 and 5, PGA is not covered.


class
openquake.hazardlib.gsim.raghukanth_iyengar_2007.
RaghukanthIyengar2007KoynaWarna
[source]¶ Implements GMPE of Raghukanth & Iyengar (2007) for the KoynaWarna region of India.
The KoynaWarna region is defined for the purpose of this GMPE by Figure 2. It is approximately a circle of 2° radius centered on 17°N 75°E.

COEFFS_BEDROCK
= <openquake.hazardlib.gsim.base.CoeffsTable object>¶ Coefficients taken from Table 2(a), p. 202.


class
openquake.hazardlib.gsim.raghukanth_iyengar_2007.
RaghukanthIyengar2007Southern
[source]¶ Implements GMPE of Raghukanth & Iyengar (2007) for southern India.
Southern India is defined for the purpose of this GMPE by Figure 2, p. 201. It is that part of India which is south of a line from from approximately 22°N 72°E to 17°N 83°E and excluding the KoynaWarna region, approximately a circle of 2° radius centered on 17°N 75°E.
Note that in Table 2(b) coefficient c1 at 0.150 s is inexplicably missing the digit before the decimal point. This was assumed to be “2”.

COEFFS_BEDROCK
= <openquake.hazardlib.gsim.base.CoeffsTable object>¶ Coefficients taken from Table 2(b), p. 203.


class
openquake.hazardlib.gsim.raghukanth_iyengar_2007.
RaghukanthIyengar2007WesternCentral
[source]¶ Implements GMPE of Raghukanth & Iyengar (2007) for westerncentral India.
Westerncentral India is defined for the purpose of this GMPE by Figure 2, p. 201. It is that part of India which is north of a line from from approximately 22°N 72°E to 17°N 83°E.

COEFFS_BEDROCK
= <openquake.hazardlib.gsim.base.CoeffsTable object>¶ Coefficients taken from Table 2(c), p. 204.
