1. Recent CSMIP/Caltrans Downhole Array Data and their Application in Site Specific Analysis H. Haddadi 1, V. Graizer 1, A. Shakal 1, P. Hipley 2 1 – California Geological Survey, Office of Strong Motion Studies 2 – California Department of Transportation (Caltrans), Office of Earthquake Engineering

2. California Strong Motion Instrumentation Program(CSMIP) operates 13 geotechnical arrays throughout the state of California, 8 of them instrumented with the support of Caltrans. Geotechnical ArrayNo. of Depths No. of Sensors Sensors’ Depth (m)Site GeologyPartner 1El Centro – Meloland4120, 30, 100, 195Deep AlluviumCaltrans 2Eureka5150, 19, 33, 56, 136Deep Soft Alluvium Caltrans 3Half Moon Bay – Tunitas4120, 5, 12, 45Alluvium, Soft Rock Caltrans 4Hayward – San Mateo Bridge5150, 10, 23, 46, 91Deep AlluviumCaltrans 5Los Angeles – La Cienega4120, 18, 100, 252Deep Soft Alluvium Caltrans 6Los Angeles – Obregon Park260, 70Alluvium, Sandstone Caltrans 7Los Angeles Vincent Thomas (East) 4120, 18, 46, 91Deep Soft Alluvium Caltrans 8Los Angeles Vincent Thomas (West) 5210, 15, 30, 91, 189Deep Soft Alluvium Caltrans

3. Geotechnical ArrayNo. of Depths No. of Sensors Sensors’ Depth (m)Site GeologyPartner 9Parkfield–Turkey Flat #1260, 24RockCSMIP 10Parkfield–Turkey Flat #2390, 11, 23AlluviumCSMIP 11San Francisco – Golden Gate Bridge 13152RockGolden Gate Br. District 12Tarzana – Cedar Hill B260, 60Soft RockROSRINE 13Treasure Island7210, 7, 16, 31, 44, 104, 122Fill, Alluvium, Rock NSF More than 60 low amplitude recordings from earthquakes with 2.4<M<7.1 were recorded. The strongest acceleration of about 0.5g was recorded at the Los Angeles La Cienega array during the M4.2 earthquake of Sep. 9, 2001 (Epicentral Distance: 2.7 km, Depth: 8 km).

4. Los Angeles - La Cienega Geotech Array M4.2 Earthquake of Sep 9, 2001 (  2.7 km) Acceleration (g) East South Up

5. M4.2 Earthquake of Sep. 9, 2001 (South Comp) and S- wave velocity profile Los Angeles - La Cienega Geotech Array S_wave Velocity (m/s)

6. Comparison of Ground Motion and One Dimensional Model M4.2 Earthquake of Sep. 9, 2001 (South Comp) Los Angeles - La Cienega Geotech Array

7. Comparison of Ground Motion and Shake91 Model at the Surface M4.2 Earthquake of Sep. 9, 2001 (South Comp) Los Angeles - La Cienega Geotech Array

8. Eureka Geotech Array P_ and S_ Wave Velocity Profile

9. M5.1 Earthquake of June 17, 2002 (  37 km) Eureka Geotech Array East Up Acceleration (g) South

10. Surface -19 m -33 m -56 m -136 m Max Acc: 0.03 (g) 0.015 0.012 0.007 Close View of Acceleration Time Histories M5.1 Earthquake of June 17, 2002 (South Comp) Eureka Geotech Array

11. Surface -19 m -33 m -56 m -136 m Correlation Analysis M5.1 Earthquake of June 17, 2002 (South Comp) Eureka Geotech Array

12. M7.1 Hector Mine Earthquake of Oct 16, 1999, East Comp (  203 km) Los Angeles - La Cienega Geotech Array Acceleration (g) Velocity (cm/sec) Displacement (cm)

13. Particle Motion of Hector Mine Earthquake (Oct. 16, 1999) at the Surface Los Angeles - La Cienega Geotech Array Horizontal PlaneVertical Plane R T R Up

14. T R R Particle Motion of Hector Mine Earthquake (Oct. 16, 1999) at the Surface Vincent Thomas Geotech Array Horizontal PlaneVertical Plane

15. Summary CSMIP operates 13 geotechnical arrays in California. More than 60 low amplitude recordings from earthquakes with 2.4<M<7.1 are recorded. Processed data of Geotechnical arrays are available at: ftp://ftp.consrv.ca.gov/pub/dmg/csmip/GeotechnicalArrayData Dynamic properties of soil (such as wave velocity and amplification) are studied using the records of Geotech arrays. Shake91 model worked well for simple source and vertical wave propagation cases. Basin Effect is observed in surface wave records of Geotech Arrays in Los Angeles area during the Hector Mine Earthquake.

16. Maximum Amplitude and Arrival Time of Displacement M7.1 Hector Mine Earthquake of Oct 16, 1999 Los Angeles – La Cienega Geotech Array

17. Maximum Amplitude of Displacement and Arrival Time at different Directions M7.1 Hector Mine Earthquake of Oct 16, 1999 Vincent Thomas Geotech Array

18. La Cienega Geotech Array Spectral Ratio Of Hector Mine Earthquake

19. Eureka Geotech Array M5.1 Earthquake of June 17, 2002 Correlation Analysis of Vertical Component Surface -19 m -33 m -56 m -136 m