New PSHA for Germany

New Generation of Probabilistic Seismic Hazard Assessment PSHA for Germany

G. Grünthal , Ch. Bosse, D. Stromeyer and R. Wahlström
GeoForschungsZentrum Potsdam, Section Seismic Hazard and Stress Field

Motivation and tasks
To provide a comprehensive update of PSHA for Germany considering  

• new and improved seismicity data
• availability of more suitable ground motion models
• latest methodological recommendations
• uncertainties in the input parameters differentiated as aleatory and epistemic leading to fractals of the output hazard

Seismicity data
An update (1000-1299 and 1994-2005) of the Grünthal & Wahlström (2003) catalogue of earthquakes since 1300 with new data from, e.g.:  

• France: LDG catalogue (Laboratoire de Détection Géophysique, CEA France) and SisFrance catalogue (2005),
• Switzerland: ECOS (Fäh et al., 2003),
• Italy: CPTI04 (CPTI Working Group, 2004),
• many special studies on single events.

Source zone models
Different regionalization models were established to account for the epistemic uncertainty:

(1) A large scale model (LSM) based on  

• large scale geological architecture,
• seismotectonics,
• seismicity is not considered.

The different tectonic regimes in the seismic zones of the LSM are considered in the ground-motion models.

Probability density functions of M_max (upper bound magnitude) based on the EPRI-method with geologically constrained truncations were developed for the source zones.

(2) Three small scale models (SSM), each representing a subdivision of the LSM according to the historically observed seismicity and the views of different expert teams. In certain parts, this model is further subdivided, e.g., in the Lower Rhine Embayment (cf. Grünthal & Wahlström, 2006).

Maximum likelihood frequency magnitude relations for each seismic source zone were derived, with uncertainities in the parameters.

Ground motion models
To account for the epistemic uncertainty, three models were used
 

• Berge-Thierry et al. (2003) using hypocentral distance r_hyp
• Abrahamson & Silva (1997) using rupture distance r_rup
• Spudich et al. (1999) using Joyner-Boore distance r_JB

To convert from r_rup and r_JB to r_hyp a user friendly approximation of distance metrics was developed based on results of Scherbaum et al. (2004). 

Examples of resulting seismic hazard maps  

Further seismic hazard maps and uniform hazard spectra are interactively available here.

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Contact: G. Grünthal

References :

Abrahamson NA, Silva WJ (1997) Empirical response spectral attenuation relations for shallow crustal earthquakes. Seismol Res Lett 68, 94-127

Berge-Thierry C, Cotton F, Scotti O, Griot-Pommera D-A, Fukushima Y (2003) New empirical spectral attenuation laws for moderate European earthquakes. J Earthquake Eng 7, 193-222

CPTI Working Group (2004) Catalogo Parametrico dei Terrimoti Italiani, versione 2004 (CPTI04). Istituto Nazionale di Geofisica e Vulcanologica, Milan, Italy http://emidius.mi.ingv.it/CPTI04/

Fäh D, Giardini D, Bay F, Bernardi F, Braunmiller J, Deichmann N, Furrer M, Gantner L, Gisler M, Isenegger D, Jiminez MJ, Kästli P, Koglin R, Masciadri V, Rutz M, Scheidegger C, Schibler R, Schorlemmer D, Schwarz-Zanetti G, Steimen S, Sellami S, Wiemer S, Wössner J (2003) Earthquakes catalogue of Switzerland (ECOS) and the related macroseismic database. Eclogae geol Helv 96: 219-236

Grünthal G, Wahlström R (2003) An M_w based earthquake catalogue for central, northern and northwestern Europe using a hierarchy of magnitude conversions. J Seismol 7(4): 507-531

Grünthal G, Wahlström R (2006) New generation of probabilistic seismic hazard assessment for the area Cologne/Aachen considering the uncertainties of the input data. Nat Hazards 38(1-2): 159-176

Grünthal G, Bosse C, Stromeyer D, Wahlström R (2006) New Generation of Probabilistic Seismic Hazard Assessment of Germany. 1st European Conference on Earthquake Engineering and Seismology, Geneva/Switzerland, 3-8 September 2006 (Poster)

LDG (2005) Data file of the Laboratoire de Détection et de Géophysique. Bruyères-le-Châtel, France

Scherbaum F, Schmedes J, Cotton F (2004) On the Conversion of Source-to-Site Distance Measures for Extended Earthquake Source Models. Bull Seismol Soc Am 94(3):1053–1069

SisFrance (2005) Data file of the BRGM, EDF, IRSN, France http://www.sisfrance.net

Spudich P, Joyner WB, Lindh AG, Boore DM, Margaris BM, Fletcher JB (1999) SEA99: a revised ground motion prediction relation for use in extensional tectonic regimes. Bull Seismol Soc Am 89(5):1156–1170