Single station sigma data set from subduction earthquakes

Nick Gregor November 30th, 2011

LTSP SSHAC Level 3 Update – Workshop 1

Subduction Earthquake Dataset

• BC Hydro SSHAC Level 3 Study

• Interface events

• Intraslab events

• Estimated Vs30m for site conditions

Subduction Earthquake Dataset Composite Data Sources: • Crouse (1988, 1991)

• Youngs et al. (1997)

• Atkinson and Boore (2003/2008)

• Zhao et al. (2006/2008)

• Cheng (2008) [Taiwan]

• Pacific Engineering and Analysis (2008) [South and Central America]

• Carrasco (2008) [Mexico]

Subduction Earthquake Dataset • 292 subduction earthquakes

– 163 Interface events (3,557 horizontal pairs) – 129 Intraslab events (6,389 horizontal pairs)

• Exclude M<6 (interface), M<5 (intraslab) – ~4,000 intraslab/2,000 interface recordings – 90% of database from Japan and Taiwan

• Interface Dataset: – Magnitudes = 6.5 -8.4 – Distances = 5 – 551 km

• Intraslab Dataset: – Magnitudes = 5.0 – 7.9 – Distances = 34 – 991 km

Subduction Earthquake Dataset

Recent Earthquakes not currently included: • 2010 Maule Chile (Mw8.8)

– 26 stations – Distance = 34-200km – Vs30m = 236-1,421m/s

• 2011 Tohoku Japan (Mw9.0) – 369 stations (K-Net, Kik-Net) – Distance = 44-989 km – Vs30m = 107-1,433 m/s

Single Station Dataset • Stations with 5 or more recordings

Region Number of Recordings

Number of Stations

Japan 56 14

Mexico 16 3

Taiwan 867 126

Sampling by Region

5 or More Recordings per site

10 or More Recordings Per Site

Single Station Sigma

Single Station Sigma