PROBLEM 4: Primary Causative Fault Identification - A Comparison between the 2008 & 2014 code changes. a) Revise your fault table to identify the "primary causative" faults within 25 kilometers of your site according to the 2008 National Seismic Hazard Map model. Document their potential magnitudes and approximate distances to your site: (NOTE: you can use your answer from Problem 1.g. from Problem Set #1. You are basically adding a Maximum Magnitude column and revising the fault order based on which faults are in the 2008 model) Earlier, you identified all of the faults within 25 km of your site (from Google Earth KML files, maps, etc.). Now you will see the "primary causative" faults" that feed into the 2008 or 2014 ground motion estimates. To do that, you will need to reference USGS Open File Report 2008-1128. Now compare the 25-km fault list you made earlier with the faults listed in "Appendix I: Parameters for Faults in California" from USGS Open File Report 2008-1128, specifically look at Tables I-1, 1-3 & 1-4. Also, notice what new or unknown faults that State, County or City general plans identified as "a potential hazard" and how they relate to your Federal fault hazard documents. If the fault you identified for your Site is not on these lists, then that fault will NOT be considered as part of a 2008-based seismic ground motion analysis. Reminder that in accordance with ASCE 7-16, some of what we do is still based on the 2008 model. As we will discuss in lecture, the 2014 National Seismic Hazard Map is already developed: see "Documentation for the 2014 Update of the United States National Seismic Hazard Maps: USGS Open File Report 2014-1091". The new model was published July 17, 2014 (roughly 9 years ago!!). The new document can be found at the following website: https://pubs.usgs.gov/of/2014/1091/. “USGS Open File Report 2008-1128" is still a currently accepted seismic model for our building code but DOES NOT contain the latest information for faulting in the US. The 2008 model was superseded in 2014 by "USGS Open File Report 2014-1091." As we discussed in lecture, we also have the 2018 fault model, which will be incorporated into the ASCE 7-22 series of building codes. Committees for drafting the new building code are forming mid- to late- 2017. As a practicing engineer or geoscientist, you should be concerned about discrepancies, differences, conflicts or potential litigation between these two seismic models. b) Revise the fault list to reflect the "primary causative” faults within 25 kilometers of your site according to the 2014 National model. Once again, list the fault potential magnitudes and approximate distances to your site according to the new & future building code changes. Document any additional faults that will be considered in your analysis. Discuss how the second set of faults will affect ground motion at your site; positively or/nnegatively. To perform this task, you need a list of active faults according to the 2014 fault model. I have placed a copy of this list named "Caltrans_Fault_Database_V2b_121312 in the GSC 3210 Canvas Folder. Use a table like the one below to compare your answer from 3a & 3b. 1 2 3 4 5 2008 National Seismic Hazard Map 2014 National Seismic Hazard Map Fault Name Distance to site Potential Maximum Magnitude Potential Distance to Fault Name Maximum site Magnitude etc...... List the primary causative faults first, in order of distance. Then, list additional faults NOT on the 2008 & 2014 lists in order of distance. NOTE: The 2008 fault model, the 2014 fault model and the United States Geological Survey Quaternary Fault Database (USGSQFD) models are all different. An example to see how the models differ, look at the Newport Inglewood fault. In the 2008 model, the Newport Inglewood alt 1 is the north Los Angeles Basin Section branch (USGS QFD). The Newport Inglewood alt 2 is the south Los Angeles Basin Section branch, and the Newport Inglewood offshore is in the ocean. The Rose Canyon fault begins at Latitude: 33.425238°, Longitude: -117.699997°./nPROBLEM 5: CALCULATING GROUND MOTION PARAMETERS As many of you already know, to design a structure you must use the most current version of the modern building code. Part of the modern building code involves implementing design modifications to account for potential seismic forces that may affect structural integrity during the "proposed structural lifetime" and in accordance with ASCE 7-10/7-16 guidelines. The classroom lecture notes will have more information regarding this topic. This procedure is accomplished by performing a Probabilistic Seismic Hazard Assessment (or PSHA) where "potential” ground motion parameters at a given site are estimated. Multiple factors control this calculation, some of which we address both in lecture and as a part of PS#3. "Site Response" is the first parameter to address. By "Site Response" I mean, "What is different at any given individual site that will control project design?" Bedrock Density is the first characteristic that must be quantified. Seismic energy travels from the hypocenter through "bedrock" outward in all directions. We need to describe the seismic energy of an earthquake and how it changes along a given travel path. To do so, we utilize density values for bedrock in conjunction with established travel-time "Primary" and "Secondary" wave parameters. The resulting energy is also affected by the total distance traveled (or the "site-to-source distance") as well as the material density changes of bedrock and soil encountered along the way. As our energy wave arrives at the "site" we will encounter "site-specific" conditions (density variations) that must be accounted for. During the 1987 Loma-Prieta earthquake, significant differences were observed between “bedrock” and “alluvium" sites. Alluvium tends to be a slower-velocity medium that amplifies total seismic energy. To model this, we adjust the estimated shear wave velocity to a lower number and estimate the total amplification of earthquake energy (acceleration). According to modern building codes, this involves a procedure developed in 1994 by the National Version 1.0 - posted 5/2/2024 Earthquake Hazards Reduction Program (NEHRP). Site classification is based on the estimated Shear Wave velocity (which is directly related to site soil density). The National Earthquake Hazards Reduction Program (NEHRP) has defined 6 soil types (Site Class A thru Site Class F) based on their shear-wave velocity in the upper 30 meters (-100 feet) of soil (VS-30). These five soil designations are part of the way we classify sites based on soil density. This density is then modeled by shear wave velocity values./n(see Table I below) General Site Class description A Hard Rock B Rock Detailed Description Includes unweathered intrusive igneous rock. Soil types A and B do not contribute greatly to shaking amplification. Volcanics, slightly weathered intrusive igneous, and high-grade crystalline metamorphic bedrock (upper range) to well-cemented and lithified coarse-grained sedimentary or low-grade metamorphic rock (lower range) Shear Wave velocity m/sec ft/sec >1,500 > 5,000 750-1,500 2,500-5,000 Blows/Foot (N Shear Stregth value) Su (psf) C Soft rock and Very dense Soil poorly-cemented coarse-grained to fine-grained sedimentary rock to dense Early to mid Pleistocene or older granular sediment 350-750 1,200-2,500 > 50 > 2,000 D Stiff Soil Mid to Late Pleistocene granular sediment or properly Enginered Fill (post 1985) 200-350 600-1,200 15-50 1,000 - 2,000 E Soft Soil Holocene granular sediment, pre-1985 artificial fill, includes some Late Quaternary muds, sands, gravels, silts and mud. Significant amplification of shaking by these soils is generally expected. <200 <600 <15 <1,000 Includes water-saturated mud and undocumented or F Unstable Soil pre-1950 artificial fill. The strongest amplification of shaking due is expected for this soil type. requires site specific measurement requires site specific measurement Table I: Modified from FEMA P-1050, USGS & ASCE 7-10 5.a.1) Calculate the appropriate NEHRP classifications for your site and apply that classification to your answer from Problem Set #2 problem 2a. You may have more than one Site Class for your site. If so, tabulate the results of surficial geologic unit and each corresponding NEHRP classification./n5.a.2) Calculate the probabilistic ground shaking analysis and site parameters based on the ASCE 7-16 building code. ASCE 7-10 is based in part on NEHRP 2009. To do this, please use the following procedures: a) Go to: http://earthquake.usgs.gov/hazards/designmaps/ b) Select either the "ATC Hazards by Location Tool" or the "SEAOC/OSHPD Seismic Design Maps Tool" c) For your Design Code Reference Document, please select “ASCE 7-10" d) Enter your Site Soil Classification A, B, C, D, E or F (calculated in Problem 4.a.1 above) e) Select your Risk Category (use "III") f) Enter your Site Latitude & Longitude g) Click "Go" (some tools) h) i) Save the PDF's (detailed reports & summaries and attach them to your submittals) Be careful!! Some of the tools cut out the lower values when you print to PDF. Tabulate your answer for accelerations in a table format. Column headings should be for the wave periods - Version 1.0 posted 5/2/2024 of 0.2 and 1.0 seconds. Row headings along the left should be "Bedrock" (for Ss, S₁), "Modified" (for SMS, SMI) and "Design" (for SDS & SDI): j) Document the "peak ground acceleration (PGA)." Was there a site modification to the PGA? (shown as PGAM, if so, state the modified peak ground acceleration) k) Document the "Seismic Design Category 1) What are the Fa and Fv amplification factors? m) What is the Long Period Transition (in seconds)? n) What is the Risk Coefficient at the 0.2 and 1.0 second periods? (shown as CRS & CRI)/nSITE 1 0.2 seconds Enter Ss acceleration here Conditions Bedrock Site Modified Site Design Enter S Ms acceleration here Enter S is acceleration here Period 1.0 seconds Enter Si acceleration here Enter S MI acceleration here Enter S D acceleration here Table Example: Probabilistic Ground Motion Parameters. Do this for your site 5.b) Repeat steps a through j in problem 4.a.2 above, only this time use ASCE 7-16 as the reference document. ASCE 7-16 is based in part on NEHRP 2015. The goal of this step is to see what is changing between the two reference documents. If possible, generate all 6 acceleration values for your site. Are the accelerations similar? Different? Review potential conflicts between ASCE 7-10 & 7-16 comment on what changed, how much, etc Be sure to review the ASCE Errata and ASCE Supplement #3 to properly calculate your Fa and Fv factors. Once you've done that, you can properly calculate your SMS, SM1, SDS and SD1 valurs in accordance with the ASCE 70-16 procedures. 5.c) How do your answers in step 4a and 4b compare to the ground motion you presented in Problem 2b (from Problem Set #2)? Problem 2b is ground motion calculations based on the publications year of the SHZ Reports (1997 & 1998 respectively for your site?). Are the PGA accelerations*, the Site Bedrock, Site modified and Site Design accelerations the same or different? How do the faults being added to each later model affect this? Elaborate on your observations. Note that some of the values may be shown as "null" and reference a specific section of the ASCE 7-16 building code. Enter that note instead of an acceleration value). (HINT: look at the supporting NEHRP documents, and the various report dates. To help you explain any differences look at USGS Open File Report 2014-1091 https://pubs.usgs.gov/of/2014/1091/ In particular, read the Abstract & Introduction of the 2014 Seismic model, you will find a discussion on between 2008 & 2014.) *Note: only calculation of PGA was performed according to 1997 Codes/n5d) Perform a Deaggregation and prepare for a Deterministic Run on the same coordinates that you run the Earthquake Ground Motion Parameters. Go to https://earthquake.usgs.gov/hazards/interactive/ This is the Unified Hazard Tool Enter the following: Site Coordinates: (make sure they are decimal format) Edition: Use "Dynamic Conterminous U.S. 2014 (v4.1.1) Exceedance Probability (a.k.a. Time Horizon): use 2,475 or 2% in 50 years Spectral Period: You are going to run this for "PGA", You should be using 259 m/s (Site Class D) Compute your Hazard Curves and your Deaggregation calculations (attach both to your submittal) PROBLEM 6: PERFORM A DETERMINISTIC SEISMIC HAZARD ANALYSIS (DSHA) 6a) Perform a Deterministic Seismic Hazard Analysis for the site using the three closest Causative Faults (from Step 3a above). Run a deterministic analysis at the peak magnitude contribution for that specific causative fault. Document the accelerations for the wave periods of 0.2 seconds, 1.0 seconds, and the peak ground acceleration. Create a table for your deterministic accelerations like the probabilistic table (see step 4.a.2 above) and compare the "deterministic accelerations" to the probabilistic accelerations for the Site. Again, column headings should be for the wave periods of 0.2 and 1.0 seconds. Row headings along the left should be "Bedrock" (for Ss, S₁), "Modified" (for SMS, SMI) and “Design” (for Sps & SDI): The following websites will provide insight and the DSHA spreadsheet you will need to run your analysis: http://peer.berkeley.edu/ https://apps.peer.berkeley.edu/ngawest/nga_models.html Download the NGA GMPE Files (on Canvas) and open the Excel Spreadsheet 1_4. This file contains the Next Generation Attenuation relationships. You will use this to determine the Peak Ground Acceleration for your site. Input your parameters in the orange box on the "Main" worksheet of the file (look at the bottom tabs of the worksheet). A list describing what each parameter is can be found a little lower in the spreadsheet. You need to differentiate which parameters are important and which ones are not./nThe spreadsheet does not have A, B, C, D, E site class designations, so you need to use the raw Vs30 values for your run. Use the following values as a guide: Site Class B = 1,070 m/s; C-425m/s; D=259m/s; E = 180 m/s; We are performing a deterministic run for our causative faults. Deterministic means "maximum possible rupture. So, in other words, ALL of these faults reach the surface. In the top left-hand portion of the Deterministic spreadsheet (MAIN tab) notice the following: This Excel file calculates the weighted average of the spectral values from the NGA models. Please enter the following weight factors for the various methods: 1. Boore and Atkinson (2008) enter Factor value 0.25 2. Campbell and Bozorgnia (2008) enter Factor value 0.25 3. Chiou and Youngs (2008) enter Factor value 0.25 4. Abrhamson (2008) enter Factor value 0.25 5. Idriss (2008) is used only for bedrock sites (a.k.a. hard granite rock at the site surface) enter Factor value of zero. Version 1.0 posted 5/2/2024 - Your magnitude will come from the 2008 National Seismic Hazard Map. Enter this in your Explanatory Variables (see the first value in the Orange Box on the Main Excel page) For the distances (next three entries in the Orange Box): Review the picture definitions on "Main" worksheet of the Excel file. We are assuming that all faults are vertical (so use 90 degrees for "8"). This means that RRUP = RJB = RX = your measured Google Earth distance./nZTOR should be set to 0 (zero) F MEASURED is 0, Z1.0 and Z2.5 use "DEFAULT" W use 15 km Aftershock Factor use "Main shock" (zero); HW Taper use Zero. For "8" use the following angles, depending on your selection (delta = Average dip of rupture plane (degrees), used in AS08, CB08 and CY08). "8" use 90 for your fault Once these entries are made, use some or all of the following values in the Vs30 box: Site Class B = 1,070 m/s; C= 760 m/s; D=259m/s; E = 180 m/s; Document your six (6) Site accelerations from the DSHA in a table for each fault. Create a summary table with the highest values. This is your summary DSHA ground motion estimate. 6b) Compare the six (6) maximum Site accelerations from your summary DSHA ground motion estimate to the six (6) Site accelerations from your PSHA. Were they higher or lower? Was this expected? Explain what happened. There is a hint in your lecture Canvas folder to help you explain any discrepancy.

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