Lightning Presentations Ridgecrest Session
Thursday, March 5 Poster 50: Safety Assessment Program Observations from the Ridgecrest Sequence & Napa Quakes
Fred Turner, SE (Consulting Structural Engineer) contact: [email protected] Overview • CA’s Safety Assessment Program: 7,000 Evaluators, 140 Trainers Why doesn’t it work?
• Lack of Training & Legal Authority
• Political, Social, & Economic Influences
3/4/2020 National Earthquake Conference 2 Sign After 5 Days of Earthquakes Employees Still Inside
What can be done to fix the Safety Assessment Program?
3/4/2020 3 Come Find Out More…
Poster 50: Safety Assessment Program Observations from the Ridgecrest Sequence & Napa Quakes
Fred Turner will be at the poster on Thursday, March 5, 6 – 6:45 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 4 Poster 72: Benefits & Risks of Sharing Intelligence after Earthquakes Through Clearinghouses: Ridgecrest Sequence
Fred Turner, SE (Consulting Structural Engineer) contact: [email protected] Overview • Fog of Information in the Aftermath of Earthquakes
• 1st & 2nd Responders face many gaps
• Clearinghouses enhance situational awareness
• Gaps in the Ridgecrest Sequence Clearinghouse: • Damage SE of Ridgecrest not visited • 2 ground motion recordings delayed • Civil & Mechanical Engineers to observe Industrial Plants • Civil Engineers to observe Sewage Basemap Credit: EERI Staff and SAP data from Ridgecrest Treatment Plants and San Bernardino County
3/4/2020 National Earthquake Conference 6 Come Find Out More!
Poster 72: Benefits & Risks of Sharing Intelligence after Earthquakes Through Clearinghouses: Ridgecrest Sequence
Fred Turner will be at the poster on Thursday, March 5, 6:45 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 7 Poster 51: Deep Learning-based Earthquake Damage Mapping with InSAR Coherence Time Series
Oliver Stephenson (Caltech); Tobias Köhne (Caltech); Eric Zhan (Caltech); Brent Cahill (Caltech); Sang-Ho Yun (JPL/Caltech); Zarchary Ross (Caltech); Mark Simons (JPL/Caltech) [email protected] @SeismOlliegist Ridgecrest Earthquakes Damage Mapping • We detect surface Mw 7.1 surface rupture ruptures, liquefaction and other anomalous changes in ground surface properties due Trona to the earthquakes from satellite measurements
Ridgecrest
Stephenson et al. (In Prep.), SAR data from Eric Fielding (JPL) 3/4/2020 National Earthquake Conference 9 Come See Our Results!
Poster 051: Deep Learning-based Earthquake Damage Mapping with InSAR Coherence Time Series Oliver Stephenson (Caltech) will be at the poster on Thursday, March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 10 Poster 52: Engineering and Geological Effects of the July 2019 Ridgecrest Earthquake Sequence
GEER Team: Jonathan Stewart (Lead), Scott Brandenberg, Pengfei Wang, Chukwuebuka Nweke, Kenneth Hudson, Silvia Mazzoni, Yousef Bozorgnia, Christine Goulet, Kenneth Hudnut, Craig Davis, Sean Ahdi, Farzin Zareian, Jawad Fayaz, Rich Koehler, Colin Chupik, Ian Pierce, Alana Williams, Sinan Akciz, Martin Hudson, Tadahiro Kishida, Collaborating Authors: Benjamin Brooks, Ryan Gold, Daniel Ponti, Katherine Scharer, Devin McPhillips, Todd Ericksen, Janis Hernandez, Jason Patton, Brian Olson, Timothy Dawson, Jerry Treiman, Christopher DuRoss, Kelly Blake, Jeffrey Bachhuber, Christopher Madugo, Joseph Sun, Andrea Donnellan, Gregory Lyzenga, Erik Conway
Contact: [email protected] Overview • Surface Fault Rupture
• Lifeline Performance
• Liquefaction and Related Ground Failure
• Ground Motions
• Structural Performance
• Imaging
• DesignSafe Integration Left: Offset of buried concrete segmented water supply pipeline crossing the M7.1 surface fault rupture. (Photo Credit: Scott Brandenberg, UCLA) Right: Surface fault rupture from M7.1 event across California Highway 178: 2.5 m right-lateral slip. (Photo Credit: Ken Hudnut, USGS)
3/4/2020 National Earthquake Conference 12 Come See Our Results!
Poster 52: Engineering and Geological Effects of the July 2019 Ridgecrest Earthquake Sequence
Sean Ahdi (Exponent/UCLA) will be at the poster on Thursday, March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 13 Poster 54: Earthquake Reconnaissance Management Challenges at Naval Air Weapons Station China Lake
Jenn Ciofolo (Reid Middleton) contact: [email protected] Overview • Challenges in managing 6,700 man hours of earthquake response time over a three week period at Naval Air Weapons Station China Lake following the July 4th and 5th M6.4 and M7.1 Searles Valley Earthquakes.
• ATC-20 Rapid and Detailed evaluations of over 600 facilities through 30 team members per day. (a) Project team coordinating in conference room. (b) Spreadsheet showing on site coordination.
3/4/2020 National Earthquake Conference 15 Come See Our Results!
Poster 54: Earthquake Reconnaissance Management Challenges at Naval Air Weapons Station China Lake Jenn Ciofolo (Reid Middleton) will be at the poster on Thursday, March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 16 Poster 55: Ridgecrest-Trona Earthquake and Fault Complex, San Bernardino County
Frank Jordan (San Bernardino County, Land Use Services) and Miles Wagner (San Bernardino County, Office of Emergency Services) contact: [email protected] Overview • Fault Surface Rupture in the Searles Valley area of San Bernardino County
• Linear, en echelon, right- stepping ground surface rupture due to active faulting
• “Miles” Fault at West End, East of Trona Rd.
• West-Northwest-striking
• View Southeast
Linear, en echelon, right-stepping ground surface rupture along the Miles Fault, West End, as a result of the Ridgecrest-Trona Fault Complex and Earthquake Sequence (Jordan, 2019) 3/4/2020 National Earthquake Conference 18 Overview • Fault Surface Rupture in the Searles Valley area of San Bernardino County
• Linear, en echelon, right- stepping ground surface rupture along the “Aguirre Ranch” Fault, due to active faulting, West of Trona Rd., Southwest of Point-of-Rocks
• “Aguirre Ranch” Fault
• Northeast-striking • View East Linear, en echelon, right-stepping ground surface rupture along the “Aguirre Ranch” Fault as a result of the Ridgecrest-Trona Fault Complex and Earthquake Sequence (Jordan, 2019) 3/4/2020 National Earthquake Conference 19 Overview • Fault Surface Rupture in the Searles Valley area of San Bernardino County
• Linear, en echelon, right- stepping ground surface rupture due to active faulting, Pinnacle Rd., East of Trona Rd.
• North-striking • View South • “Miles” Fault • “Trona” Fault • “Aguirre Ranch” Fault Linear, en echelon, right-stepping ground surface rupture • “Pinnacles” Fault due to active faulting as a result of the Ridgecrest-Trona • “West Searles Valley” Fault Fault Complex and Earthquake Sequence (Jordan, 2019) 3/4/2020 National Earthquake Conference 20 Overview • Fault Surface Rupture in the Searles Valley area of San Bernardino County
• Linear, en echelon, right- stepping ground surface rupture due to active faulting
• “Pinnacles” Fault, Pinnacle Road, North of Pinnacles Natural Landmark
• Northeast-striking
• View Southwest Linear, en echelon, right-stepping ground surface rupture along the “Pinnacles” Fault as a result of the Ridgecrest- Trona Fault Complex and Earthquake Sequence (Jordan, 2019) 3/4/2020 National Earthquake Conference 21 Overview • Fault Surface Rupture in the Searles Valley area of San Bernardino County
• Linear, en echelon, right- stepping ground surface rupture due to active faulting
• “Pinnacles” Fault, Pinnacle Road, North of Pinnacles Natural Landmark
• Northeast-striking
• View Northeast Linear ground surface rupture along the “Pinnacles” Fault as a result of the Ridgecrest-Trona Fault Complex and Earthquake Sequence (Jordan, 2019)
3/4/2020 National Earthquake Conference 22 Overview • Fault Surface Rupture in the Searles Valley area of San Bernardino County
• Linear, en echelon, right- stepping ground surface rupture due to active faulting, Pinnacle Rd., west of Randsburg Wash Rd.
• “West Searles Valley” Fault
• Northwest-striking
• View Southwest Linear, en echelon, right-stepping ground surface rupture due to active faulting as a result of the Ridgecrest-Trona Fault Complex and Earthquake Sequence (Jordan, 2019)
3/4/2020 National Earthquake Conference 23 Come See Our Results!
Poster 55: Ridgecrest-Trona Earthquake and Fault Complex, San Bernardino County Frank Jordan (San Bernardino County) and Miles Wagner (San Bernardino County) will be at the poster on Thursday, March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 24 Poster 56: San Bernardino County Emergency Response to July 4th-5th Ridgecrest-Trona Earthquake Complex
Miles Wagner (San Bernardino Co Fire Office of Emergency Services); Frank Jordan (San Bernardino Co Land Use Services) contact: [email protected] Timeline
10:33 a.m. July 4th: Mag 6.4 EQ Searles Valley/ Ridgecrest
• 10:35 a.m. - Magnitude 4.7 aftershock
• 12:15 p.m. - OA EOC activated Level 3 / Ridgecrest Hospital evacuated
• 1:30 p.m. - Multiple SCE power outages in the Trona Region
• State Operations Center (SOC) activated to Level 2
• Governor Newsom declares State of Emergency for Kern County for the “Ridgecrest Earthquake”
3/4/2020 National Earthquake Conference 26 Overview
July 5TH:
• 8:00 a.m. - Ridgecrest Hospital still closed
• 10:15 a.m. – “Boil Water” Notice issued in Trona • Searles Valley Water Company • Portions of Trona without running water, restoration estimated July 6
• American Red Cross (ARC) shelter opened in Ridgecrest
• 7:00 p.m. - OA EOC transitions from Level 3 to Duty Officer WE ALL THOUGHT WE WERE GOOD TO GO!
• County OES coordinates with Land Use Services (LUS) to send a team to conduct community needs assessment in Trona
3/4/2020 National Earthquake Conference 27 Timeline
8:31 p.m. July 5TH: Mag 7.1 EQ near Trona
• 10:30 p.m. - OA EOC upgraded to Level 2 activation
• Liaison Officers from National Guard/County Dept. respond to OA EOC
• County Fire Divisions move equipment onto their pads and begin assessing damage
• Numerous power outages and gas leaks in the affected area
• Reports of damage and injuries Trona / Ridgecrest area
3/4/2020 National Earthquake Conference 28 Overview
July 6th:
• Agency reps from ICEMA/PH/Sheriff/Utilities onsite at OA EOC
• County Fire heavy USAR assets onscene, operations underway in Trona and Fire continues assessing injuries and damage
• 1:04 a.m. - SB County proclaims a Local Emergency
• Governor issues a Proclamation of State of Emergency and requests a Presidential Declaration of Major Emergency
• Caltrans and County Road crews working to open roads
• Union Pacific Railroad stops all operations until completion of full survey and inspections
3/4/2020 National Earthquake Conference 29 Statistics
• OAEOC was activated for 18 days 24 hr. operations • Height of event 58+ EOC responders • Additional personnel staffed the CPOD, LAC, and Recovery Center (20+) • To date $4.6 million in response costs
Enter figure caption and credits. (a) USGS
3/4/2020 National Earthquake Conference 30 Access Issues
3/4/2020 National Earthquake Conference 31 Infrastructure • Briefly describe the high-level focus of your poster
Enter figure caption and credits. (a) Aliquam et turpis ursus,
3/4/2020 National Earthquake Conference 32 Initial Response – July 6 – 7th • Briefly describe the high-level focus of your poster
3/4/2020 National Earthquake Conference 33 OES Incident Management July 8 - 20 • Briefly describe the high-level focus of your poster
3/4/2020 National Earthquake Conference 34 Statistics
• OES Staff – 4 • Incident Management • Logistics • LAC Support
• CERT Personnel – 52
• ECS Personnel – 26
• VOAD Personnel – 75
• Volunteer hours – 6,500+
3/4/2020 National Earthquake Conference 35 Commodity Point of Distribution – CPOD July 6 -20
• Briefly describe the high-level focus of your poster
3/4/2020 National Earthquake Conference 36 CPOD • Briefly describe the high-level focus of your poster
3/4/2020 National Earthquake Conference 37 Statistics
• CPOD Distribution: • 21,600 cases of bottled water (450 pallets) • 1,275 bottles of one-gallon bottled water • 281 cases of Gatorade • 46,200 pounds of ice • 45 cases of diapers • 280 waterless hygiene kits • 640 2.5 gallon bottles for non- potable water • 235 cases of MREs • 34,000 gallons non potable water • 28,000 gallons potable water
3/4/2020 National Earthquake Conference 38 LOCAL ASSISTANCE CENTER – LAC July 10-20
• Briefly
3/4/2020 National Earthquake Conference 39 LAC Statistics
• LAC = 646 clients • Resident calls for damage assessment/other services = 78 • ARC Shelter Ridgecrest = 45 utilized services/37 stayed at the shelter • EHS = 10 food facilities were inspected • ACC = 25 dogs and cats were impounded/19 dogs/cats remained at the shelter/total 74 field service calls were completed • MSU = 94 clients were seen including 6 home visits and 2 medical transports to Ridgecrest Regional Hospital
3/4/2020 National Earthquake Conference 40 Recovery Center July 19th to August 8th
• LAC closes and transitions to Recovery Center to focus on those with continuing needs and case management • Public Health • Behavioral Health • Aging and Adult Services • Land Use Services • ARC Client Services
• CPOD closes
• SBA DLOC opens August 9th
3/4/2020 National Earthquake Conference 41 Community Outreach
3/4/2020 National Earthquake Conference 42 LAC STATISTICS • Behavioral Health team provided behavioral health services at the CPOD and LAC. • 47 Home Visits Conducted
• RECOVERY OPERATIONS/ COST RECOVERY CONTINUES
3/4/2020 National Earthquake Conference 43 Lessons Learned • High Heat Event (116) • 140 Miles Out • CPOD Material Handling • Incident Messaging/ Community Outreach • Dept. Contact list • Staff Travel/Hotel Rooms • Telecommunications • Incident Management
3/4/2020 National Earthquake Conference 44 Come See Our Results!
Poster 56: San Bernardino County Emergency Response to July 4th-5th Ridgecrest-Trona Earthquake Complex
Miles Wagner will be at the poster on Thursday, March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 45 Poster 57: Ridgecrest-Trona Earthquake Complex, Liquefaction and Lateral Spreading, San Bernardino County
Miles Wagner (San Bernardino County, Office of Emergency Services) and Frank Jordan, Jr. (San Bernardino County, Land Use Services) contact: [email protected] Overview • Liquefaction in the Searles Valley area of San Bernardino County
• Sand Boils at the Trona Rest Area, South of the intersection of Trona Road and Center Street, Trona
• View Northeast
Sand boils at Trona Rest Area as a result of the Ridgecrest-Trona Fault Complex and Earthquake Sequence (Jordan, 2019)
3/4/2020 National Earthquake Conference 47 Overview • Liquefaction in the Searles Valley area of San Bernardino County
• Intersection of Main Street and Prospect Avenue, Downtown Trona
• View West
Shoved curb and tented asphalt, Downtown Trona, as a result of the Ridgecrest-Trona Fault Complex and Earthquake Sequence (Jordan, 2019)
3/4/2020 National Earthquake Conference 48 Overview • Liquefaction in the Searles Valley area of San Bernardino County
• In front of former Esparza restaurant, Main Street, Downtown Trona
• View South
Shoved sidewalk resulting in tented concrete and tiles, Downtown Trona as a result of the Ridgecrest-Trona Fault Complex and Earthquake Sequence (Jordan, 2019)
3/4/2020 National Earthquake Conference 49 Overview • Liquefaction in the Searles Valley area of San Bernardino County
• Liquefaction shatter and random fractures, Pinnacle Road, North of Pinnacles Natural Landmark
• View Southwest
Liquefaction effects, randomly fractured soils north of the Pinnacles Natural Landmark as a result of the Ridgecrest- Trona Fault Complex and Earthquake Sequence (Jordan, 2019) 3/4/2020 National Earthquake Conference 50 Overview • Liquefaction in the Searles Valley area of San Bernardino County
• Lateral spread, south of Magnolia Avenue, Trona
• View Southwest
Lateral spread, parallel, down-to-the-lake fractured soils Road as a result of the Ridgecrest-Trona Fault Complex and Earthquake Sequence (Jordan, 2019)
3/4/2020 National Earthquake Conference 51 Come See Our Results!
Poster 57: Ridgecrest-Trona Earthquake Complex, Liquefaction and Lateral Spreading, San Bernardino County Miles Wagner (San Bernardino County) and Frank Jordan (San Bernardino County) will be at the poster on Thursday, March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 52 Poster 58: Survey of Damaged Tufa Pinnacles in Trona Following the 2019 Ridgecrest Earthquake Sequence Christine Goulet, Xiaofeng Meng (SCEC, USC); Andrea Donnellan, Greg Lyzenga (Jet Propulsion Laboratory, Caltech) contact: [email protected] Damaged Tufa Spires Trona Pinnacles • Damage to Fragile Geologic Features (FGFs) can help constrain ground motion levels from earthquakes over time.
• On July 12, we documented the damage/intact state of a large number of tufa spires FGFs at the Trona Pinnacles, May 30, 2001, J. Brune July 12, 2019, C. Goulet following the M6.4 and M7.1 events. Location map relative to the M7.1 fault trace.
• A subset of spires were imaged using unmanned aerial vehicles (UAVs), providing volumetric data.
• Tufa spires are more fragile and prone to July 12, 2019 weathering and degradation than other FGFs, but their study as part of a well- recorded event can nonetheless help us refine techniques for the use of other FGFs
in ground motion assessment. Initial spire numbering.
July 14, 2019
3D image of Spire 01 from UAV survey. The volume the fallen rock is estimated at 9.5 m3, for comparison, the remaining spire is estimated at 634 m3.
National Earthquake Conference SCEC 54 Come See Our Results!
Poster 58: Survey of Damaged Tufa Pinnacles in Trona Following the 2019 Ridgecrest Earthquake Sequence
Contact [email protected] for a personalized tour of the poster.
3/4/2020 National Earthquake Conference 55 Poster 59: Seismic Shock to the Electric System
John Dai (Southern California Edison); John Eidinger (G&E Engineering Systems, Inc.); and Colby Wong (Southern California Edison) contact: [email protected] Overview
• This study addresses the damage, performance, response, and recovery of the electric system with a focus on the distribution system throughout Ridgecrest and Trona.
• There are only a few strong motion instruments near the epicenter, this study explores the ground motion and soil conditions utilizing information gathered from equipment damage and performance.
• We believe that the ShakeMap motions for the Searles,
Trona, and specific areas within Ridgecrest are under- Liquefaction zones (blue zones), Trona Area. (G&E Engineering Systems, Inc., 2019) reported in the ShakeMap.
3/4/2020 National Earthquake Conference 57 Come See Our Results!
Poster 59: Seismic Shock to the Electric System
John Dai (Southern California Edison) will be at the poster on Thursday, March 5, 2020
6:00 pm – 7:30 pm, Grande Ballroom A,
or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 58 Poster 60: Cross-Fault Interaction in the July 2019 Ridgecrest Earthquake Sequence
Ken Hudnut (USGS), J. Hernandez (CGS), K. Blake (Navy), I. Pierce (UNR), A. Williams (ASU), R. Koehler (UNR), B. Brooks (USGS), T. Ericksen (USGS), A. Morelan (CGS), E. Haddon (USGS), D. Shelly (USGS), D. Mencin (UNAVCO), C. Milliner (JPL), G. Seitz (CGS), L. Seeber (LDEO), J. Pacheco (OVSICORI) contact: [email protected] Overview
• M 6.4 then a ~34.3 hour delay, with abundant cross-fault interaction throughout this interval, followed by M 7.1 and its aftershocks; we have satellite & airborne imagery, GPS, and seismicity data
• Cross-fault interaction, reminiscent of 1987 Superstition Hills earthquake sequence; the fluid diffusion delay (poroelastic re-equilibration) mechanism proposed by Hudnut et al. (GRL, 1989) for 1987 delay can explain the 2019 delay (but is non-unique)
• Cross-fault interaction occurred at many scales and is clearly evident in 2019 seismicity; M 6.4 => M 7.1 is not a simple case
• Did 1987 appear simpler because it was smaller and the data were less clear? For example, in 1987 we had no surface fault rupture observations on the cross- faults prior to the mainshock's occurrence; must act quickly in future to capture complexity Left-stepping NW-SE en echelon fractures associated with the M 6.4 foreshock (helicopter • Faulting in 'the intersection' area after the M 6.4 & before the M 7.1 photo by K. Hudnut, taken before the M 7.1) definitely did include NW-SE ruptures, some of which re-ruptured in NW-SE & NE-SW re-rupture occurred in the M 7.1 M 7.1
• Part of the NE-SW cross-fault near 'the intersection'National Earthquake re-ruptured Conference in 60 M 7.1 Come See Our Results!
Poster 60: Cross-Fault Interaction in the July 2019 Ridgecrest Earthquake Sequence Ken Hudnut (USGS) will be at the poster on Thursday, March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
National Earthquake Conference 61 Poster 63: Surface rupture patterns of the Ridgecrest earthquakes: Implications for the Walker Lane
Rich Koehler (University of Nevada, Reno) contact: [email protected] Overview
• Drone models of the Ridgecrest earthquake ruptures are used to highlight rupture patterns and the width of deformation.
• Orthogonally oriented fault sets are common in the Walker Lane.
• Historical earthquakes and microseismicity in the Walker Lane indicate that Ridgecrest style ruptures may occur elsewhere in the Walker Lane. Drone imagery of the M6.4 Ridgecrest rupture and similarities in fault geometry throughout the Walker Lane 3/4/2020 National Earthquake Conference 63 Come See Our Results!
Poster 63: Surface rupture patterns of the Ridgecrest earthquakes: Implications for the Walker Lane
Rich Koehler (University of Nevada, Reno) will be at the poster on Thursday, March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 64 Poster 65: Rapid UAV Imaging of Ground Deformation following the M6.4 Earthquake of the Ridgecrest Sequence Andrew Lyda (UW), Scott J. Brandenberg (UCLA), Tristan Buckreis (UCLA), Omar Issa (UCLA), Jonathan P. Stewart (UCLA), Joseph Wartman (UW), J. Sean Yeung (UW), and Zhengxiang Yi (UCLA) contact: [email protected] Overview
• RAPID facility support of GEER reconnaissance investigation
• Quick deployment to image surface fault rupture across multiple kms
• Post-processed digital products including high- resolution orthomosaics and digital surface models
• All data is openly available on Designsafe
Digital surface model showing surface fault rupture
3/4/2020 National Earthquake Conference 66 Come See Our Results!
Poster 65: Rapid UAV Imaging of Ground Deformation following the M6.4 Earthquake of the Ridgecrest Sequence
Joe Wartman (UW RAPID) will be at the poster on Thursday, March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 67 Poster 066: Near-Field Ground Motions from the M7.1 Ridgecrest, California, Earthquake: Subdued Shaking due to Non-linear Site Response
Susan E. Hough (US Geological Survey), Eric Thompson (USGS), Grace Parker (USGS), Robert W. Graves (USGS), Kenneth Hudnut (USGS), Jason Patton (CGS), Timothy Dawson (CGS), Tyler Ladinsky (CGS), Michael Oskin (UCD), Krittanon Sirorattanakul (Caltech), Kelly Blake (NAWS), Annemarie Baltay (USGS) and Elizabeth Cochran (USGS) contact: [email protected] Overview
• Limited damage in Ridgecrest
• MMI highly consistent with PGA
• Near-field mainshock MMI < IPE
• Near-field MMI/PGA ~ NGA GMPE
• H-V Spectral Ratio --deamplification for f>2 Hz at alluvial sites --pervasive non-linearity
• Non-linear GMPE terms predict observations
• No non-linear terms in IPE --overprediction of intensities Simplified Shakemap for M7.1 mainshock. Symbols indicate observed intensity values. Inset figure shows average H-V spectral ratios for alluvial sites (red) and rock sites (green).
3/4/2020 National Earthquake Conference 69 Come See Our Results!
Poster 066: Near-Field Ground Motions from the M7.1 Ridgecrest, California, Earthquake: Subdued Shaking due to Non-linear Site Response Susan Hough(USGS) will be at the poster on Thursday, March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 70 Poster 70: Stress Drop and Ground-Motion Source Characterization of the July 2019 M7.1 and M6.4 Ridgecrest Earthquake Sequence
Annemarie Baltay (USGS Moffett Field); Grace Parker (USGS Moffett Field), Rachel Abercrombie (BU), Eric Thompson (USGS Golden), John Rekoske (USGS Golden) contact: [email protected] Q: what IS stress drop?
Earthquake Physics Earthquake Ground Motion ▪ basic earthquake source parameter ▪ relates moment to high-frequency ▪ estimate of earthquake energy ▪ controls high-f ground motion ▪ related to source dimension ▪ spatially varying, repeatable locations?
… but much uncertainty still exists
3/4/2020 join the Ridgecrest stress drop study! email me: [email protected] 72 Ridgecrest stress drop comparison study Arias intensity stress drops GMPE PGA event terms ▪ M7.1, M6.4 and many aftershocks on surface rupture ▪ Estimate stress drop through multiple methods: - fc fitting; Arias intensity; PGA GMPE event terms ▪ Even within our study, differences arise M7.1: Ds=3.0MPa M6.4: Ds =3.6MPa ▪ Propose: Comparison/Validation using Ridgecrest data ▪ Collect Ridgecrest stress drops from other researchers - Correlations between different methods Automated Brune Ds fits per Ridgecrest stress drop from Brune spectral fitting - Uncertainty and variability within methods. 105 horizontal component over
104 all stations using gmprocess GMPE PGA event - Connection to ground motion parameters. terms correlate with 103
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- Dependencies on source parameters: depth, P
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10-2 3.5 4 4.5 5 5.5 6 6.5 7 7.5 Magnitude join the Ridgecrest stress drop study! email me: [email protected] Come See Our Results and Chat! join the Ridgecrest stress drop study! email me: [email protected] Poster #70 Stress Drop and Ground-Motion Source Characterization of the July 2019 M7.1 and M6.4 Ridgecrest Earthquake Sequence Also see Poster #61 by Grace Parker Repeatable Source-, Path-, and Site effects of the July 2019 M7.1 Ridgecrest Earthquake Sequence
Annemarie (that’s me!) will be at the poster on Thursday, March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 74 Poster #73: Building Damage due to Liquefaction in the Ridgecrest Earthquake Sequence
Kenneth S. Hudson (UCLA/Wood); Marty B. Hudson (Turner); and Ken O’Dell (MPH Structural Engineerings) contact: [email protected] Overview • Widespread liquefaction-induced lateral spreading in Trona and Argus during both M6.4 and M7.1 events
• Lateral spreading (NOT liquefaction- induced settlement) caused building damage
• Structures in liquefaction areas also experienced increased shaking-induced damage
Photo of Liquefaction-Induced Lateral Spreading in Trona, CA Photo credits: Kenneth Hudson (2019)
3/4/2020 National Earthquake Conference 76 Photo of Damage to the Esparza Restaurant in Trona, CA Photo credits: Marty Hudson (2019) 3/4/2020 National Earthquake Conference 77 Come See Our Results!
Poster #73: Building Damage due to Liquefaction in the Ridgecrest Earthquake Sequence
Kenneth Hudson (UCLA/Wood) will be at the poster on Thurs., March 5, 6 – 7:30 pm, Grande Ballroom A, or contact [email protected] to schedule a time to meet.
3/4/2020 National Earthquake Conference 78 Lightning Presentations Ridgecrest Session
Thursday, March 5