Site-Specific Seismic Hazard And Site Response Analyses And . - Alaska
Site-Specific Seismic Hazard and SiteResponse Analyses and Development ofEarthquake Ground Motions for thePort of Anchorage Expansion ProjectIvan WongPrincipal Seismologist/Vice PresidentSeismic Hazards GroupURS CorporationOakland, CAandYoussef HashashAssociate ProfessorUniversity of Illinois at Urbana-ChampaignUrbana, ILAlaska Seismic Hazards Safety Commission7 January 2008SEISMIC HAZARDS
Introduction URS Corporation has performed a site-specific probabilisticseismic hazard analysis (PSHA) and a deterministic seismichazard analysis (DSHA). A site response analysis has been performed to estimate theground motions at the top of the soil column. We have developed Maximum Considered Earthquake(MCE), Contingency Level Earthquake (CLE), and OperatingLevel Earthquake (OLE) ground motion parameters.SEISMIC HAZARDS2
Introduction (cont’d.) These three design earthquakes have correspondingexceedance probabilities of 50%, 10%, and 2% in 50 yearsor return periods of 72, 475, and 2475 years, respectively. This study is an update of a 2004 evaluation, which wasbased on the 1999 USGS National Hazard Maps for Alaska.SEISMIC HAZARDS3
Purpose The primary objective of this study is to estimate thefuture levels of ground motions at the site that will beexceeded at a specified probability. Time-independencewas assumed. Available geologic and seismologic data including inputsused in the USGS Alaska hazard maps (Wesson et al.,1999; 2007) have been used to evaluate and characterize1) potential seismic sources,2) the likelihood of earthquakes of various magnitudesoccurring on those sources, and3) the likelihood of the earthquakes producing ground motionsover a specified level.SEISMIC HAZARDS4
Scope of Work Task 1 – Seismic Source Characterization Task 2 – Evaluation of Historical and Contemporary Seismicity Task 3 – Selection of Attenuation Models Task 4 – Probabilistic and Deterministic Seismic Hazard Analyses Task 5 – Development of Time Histories Task 6 – Site-Specific Response Analysis Task 7 – Development of Site-Specific MCE and ODE Spectraand Time Histories Task 8 – Interim Memos and Final ReportSEISMIC HAZARDS5
Aleutian and Alaskan Subduction Zone and LargeHistorical Earthquakes (M 6.5), 1898 to 2006SEISMIC HAZARDS6
Alaskan Subduction ZoneSEISMIC HAZARDS7
Isoseismal Map of the 28 March 1964 M 9.2Great Alaskan EarthquakeSEISMIC HAZARDS8
1964 M 9.2 Rupture AreaSource: Mavroedis et al., 2008SEISMIC HAZARDS9
Historical Seismicity and SignificantEarthquakes (M 3.0) 1898 – 2007SEISMIC HAZARDS10
Seismic Hazard Model Logic TreeVS30 760 m/sec(Dutta et al., 2007)SEISMIC HAZARDS11
Neogene and Quaternary FaultsWithin 200 km of the PortSEISMIC HAZARDS12
Neogene and Quaternary Faultsin the Vicinity of the PortSEISMIC HAZARDS13
Seismic Source Parameters for Faults in theVicinity of the Port of AnchorageSEISMIC HAZARDS14
Seismic Source Parameters for Faults in theVicinity of the Port of Anchorage (cont.)SEISMIC HAZARDS15
Seismic Source Parameters for Faults in theVicinity of the Port of Anchorage (cont.)SEISMIC HAZARDS16
Crustal Earthquakes(M 4.5 to 7.3, Depth of 25 km) Used inRecurrence CalculationsSEISMIC HAZARDS17
enceIntervalsM 6: 21 yrsM 7: 270 yrsSEISMIC HAZARDS18
Seismicity Cross-Section Through AlaskanSubduction Zone Near AnchorageVeilleux and Doser, 2007SEISMIC HAZARDS19
Model of Megathrust and Intraslab Used inthe Hazard AnalysisSEISMIC HAZARDS20
Seismic Source Parameters for the AlaskanSubduction ZoneSEISMIC HAZARDS21
Intraslab Earthquakes(M 5.0 to 7.5, Depth of 30 to 120 km)Used in RecurrenceSEISMIC HAZARDS22
rvalsM 6: 3 yrsM 7: 38 yrsSEISMIC HAZARDS23
Attenuation RelationshipsCrustal (NGA)Weights Chiou and Youngs (2008)0.25Abrahamson and Silva (2008)0.25Campbell and Bozorgnia (2007)0.25Boore and Atkinson (2007)0.25Intraslab Youngs et al. (1997)0.50Atkinson and Boore (2003)0.50Megathrust Youngs et al. (1997)(0.4)Atkinson and Boore (2003)(0.4)Gregor et al. (2002)(0.2)SEISMIC HAZARDS24
Comparison ofAttenuationModels forDifferentSeismicSource TypesSEISMIC HAZARDS25
Seismic HazardCurves for PeakHorizontalAccelerationSEISMIC HAZARDS26
Seismic HazardCurves for 1.0Sec HorizontalSpectralAccelerationSEISMIC HAZARDS27
Seismic SourceContributionsto Mean PeakHorizontalAccelerationHazardSEISMIC HAZARDS28
Seismic SourceContributionsto Mean 1.0Sec HorizontalSpectralAccelerationHazardSEISMIC HAZARDS29
Magnitude and Distance Contributions to the MeanPeak Horizontal Acceleration Hazard at 72-YearReturn PeriodSEISMIC HAZARDS30
Magnitude and Distance Contributions to the MeanPeak Horizontal Acceleration Hazard at 475-YearReturn PeriodSEISMIC HAZARDS31
Magnitude and Distance Contributions to theMean Peak Horizontal Acceleration Hazard at2,475-Year Return PeriodSEISMIC HAZARDS32
Magnitude and Distance Contributions to the Mean1.0 Sec Horizontal Spectral Acceleration Hazard at72-Year Return PeriodSEISMIC HAZARDS33
Magnitude and Distance Contributions to the Mean1.0 Sec Horizontal Spectral Acceleration Hazard at475-Year Return PeriodSEISMIC HAZARDS34
Magnitude and Distance Contributions to theMean 1.0 Sec Horizontal Spectral AccelerationHazard at 2,475-Year Return PeriodSEISMIC HAZARDS35
Site-Specific Probabilistic SpectralAccelerationsSEISMIC HAZARDS36
Comparison of Site-Specific Versus2007 USGS Map Values2% in 50 YearsSASite-Specific2007 USGS% ChangePGA0.580.69-16%0.2 sec1.181.55-24%1.0 sec0.440.52-15%SEISMIC HAZARDS37
Controlling Earthquakes (Modes)SEISMIC HAZARDS38
5%-DampedUniform HazardSpectraSEISMIC HAZARDS39
Median and 84thHorizontalAccelerationResponseSpectra for theM 7.7 CastleMountain FaultMaximumEarthquakeSEISMIC HAZARDS40
Median and 84thHorizontalAccelerationResponseSpectra for theM 7.5 IntraslabMaximumEarthquakeSEISMIC HAZARDS41
Median and 84thHorizontalAccelerationResponseSpectra for theM 9.2MegathrustMaximumEarthquakeSEISMIC HAZARDS42
Comparison ofUHS andDeterministicScenarioSpectraSEISMIC HAZARDS43
Synthetic Acceleration Time Historiesfor AnchorageSource: Mavroedis et al., 2008SEISMIC HAZARDS44
UHS and ScaledMegathrustSpectraSEISMIC HAZARDS45
Summary of Seed Time HistoriesSEISMIC HAZARDS46
Time Histories Spectrally Matched to Horizontal475-Year Return Period Target UHS, Intraslab Event(M 7.1, D 74.7 km) 1949 Western WashingtonEarthquake, OlympiaSEISMIC HAZARDS47
Site Response AnalysisSEISMIC HAZARDS48
Updated VS – 4 ProfilesShear Wave Velocity [ft/s]05001000 1500 2000 2500001000 1500 2000 2500Bootlegger CoveFormationElevation [ft]-150-200-2500-50-50-100Bootlegger l5001000 1500 2000 25000FillElevation [ft]Sand/Silt/Clay-100Elevation [ft]5000-50Shear Wave Velocity [ft/s]Shear Wave Velocity [ft/s]FillBootlegger 0-350-400-400-400-450-450GlacialFluvialB/C Boundary-450Profile 2a-Lower (2004)T-BH-AP-7423T-BH-AP-7442Laird & StokoeTB-12Profile 2a (mean)μ σProfile 2a-Upper (2004)T-BH-AP-7428KAC ReportTB-01TB-20μ σProfile 1a-Lower (2004)Profile 1a-Upper (2004)Profile 1a (mean)μ σμ σProfile 1a (mean)Profile 1b (mean)Profile 2a (mean)Profile 2b (mean)SEISMIC HAZARDS49
Updated Shear Modulus Reduction andDamping CurvesBootlegger Cove Formation without the fill1.00.6β [%]G/Go0.80.40.20.00.00010.0010.010.1Shear Strain - γ - [%]Vucetic & Dobry PI - 15%Darendeli Middle BCFDarendeli Top BCFDarendeli Bottom BCF13025201510500.00010.0010.010.11Shear Strain - γ - [%]Vucetic & Dobry PI - 15%Darendeli Middle BCFDarendeli Top BCFDarendeli Bottom BCFSEISMIC HAZARDS50
Typical Results: Different ModelsProfile 1a - Surface - 10% in 50 yearsProfile 1a - Surface - 2% in 50 years1.21.21.01.0EL N000EL N090MR N0000.8Sa [g]Sa [g]0.80.60.4MR N090MRDF N0000.6MRDF N090MRDF D N0000.4MRDF D N0900.20.20.00.010.00.010.11Period iod [sec]SEISMIC HAZARDS51
Typical Results: All MotionsProfile 2a - Surface - 2% in 50 yearsProfile 2a - Surface - 10% in 50 years1.61.2MRDF D N0001.4MRDF D N0901.0MRDF D M1801.2MRDF D Olympia0.8Sa [g]Sa [g]1.00.80.6MRDF D Mega009MRDF D Mega0050.6MRDF D N000MRDF D N0900.4MRDF D M1800.40.20.00.01MRDF D Olympia0.20.11Period [sec]100.00.01MRDF D Mega009MRDF D Mega0050.1110Period [sec]SEISMIC HAZARDS52
Conclusions The probabilistic hazard at the Port is expectedlymoderate to high with a 2,475-year return period meanPGA of 0.58 g. The controlling seismic source at the Port is the WadatiBenioff zone with a significant contribution from the 1964megathrust at long periods ( 2 sec). The site-specific ground motions for the Port are about20% lower than the USGS National Hazard Maps. The useof more recent attenuation relationships probably accountfor this difference.SEISMIC HAZARDS53
Conclusions (cont’d.) The Castle Mountain fault is not a significant contributorrelative to the subduction zone in large part due to thelower ground motions resulting from the NGA models. The site response analysis indicates that at higher levelsof ground motions e.g., 2% and 10% in 50 years, there isdeamplification of ground motions due to nonlinear soilresponse and the impedance contrast between theBootlegger Cove Formation and the overlying fill. At lower levels of ground motions, there is someamplification e.g., 50% in 50 years.SEISMIC HAZARDS54
SEISMIC HAZARDS. Introduction URS Corporation has performed a site-specific probabilistic seismic hazard analysis (PSHA) and a deterministic seismic hazard analysis (DSHA). A site response analysis has been performed to estimate the ground motions at the top of the soil column. We have developed Maximum Considered Earthquake
To develop the seismic hazard and seismic risk maps of Taungoo. In developing the seismic hazard maps, probabilistic seismic hazard assessment (PSHA) method is used. We developed the seismic hazard maps for 10% probability of exceedance in 50 years (475 years return period) and 2 % probability in 50 years (2475 years return period). The seisic
Peterson, M.D., and others, 2008, United States National Seismic Hazard Maps ․ Frankel, A. and others, Documentation for the 2002 Update of the National Seismic Hazard Maps ․ Frankel, A. and others, 1996, National Seismic Hazard Maps Evaluation of the Seismic Zoninig Method ․ Cornell, C.A., 1968, Engineering seismic risk analysis
Seismic hazard parameters are estimated and mapped in macro level and micro level based on the study area. The process of estimating seismic hazard parameters is called seismic . maps of Indian Regions earlier, based on several approaches. This includes probabilistic seismic hazard macrozonation of Tamil Nadu by Menon et al. (2010), Seismic .
This analysis complied with these provisions by using the USGS 2014 National Seismic Hazard Map seismic model as implemented for the EZ-FRISK seismic hazard analysis software from Fugro Consultants, Inc. For this analysis, we used a catalog of seismic sources similar to the one used to produce the 2014 National Seismic Hazard Maps developed by .
dominate estimates of seismic hazard in the vicinity of their traces. Figure 7c shows the seismic hazard maps after overlaying seismic hazard estimates for the faults on the map based on instrumental data. At 10% probability of exceedance, the area with the highest level of seismic hazard falls within the SSA and between the LJF and the SCF.
2.4 UNCERTAINTIES IN THE SEISMIC HAZARD ASSESSMENT 35 2.5 SEISMIC HAZARD RESULTS 37 2.5.1 Hazard curves for selected cities 37 2.5.2 Uniform hazard spectra for selected cities 39 2.5.3 Seismic hazard maps 40 2.5.4 Set of stochastic scenarios 43 2.5.5 Comparison of the results with the elastic design spectra defined in NSCE-02 and Eurocode-8 43
the seismic design of dams. KEYWORDS: Dam Foundation, Probabilistic Seismic Hazard Maps, Seismic Design 1. INTRODUCTION To perform seismic design or seismic diagnosis, it is very important to evaluate the earthquake hazard predicted for a dam site in order to predict earthquake damage and propose disaster prevention measures. There are two .
TANK DESIGN & DETAILING Introduction The API 650 standard is designed to provide the petroleum industry with tanks of adequate safety and reasonable economy for use in the storage of petroleum, petroleum products, and other liquid products commonly handled and stored by the various branches of the industry. This standard does not present or establish a fixed series of allowable tank sizes .
