Project Grant G25AP00371

PROJECT TITLE: USING DID YOU FEEL IT? DATA TO MAP SPATIALLY VARIABLE SITE AMPLIFICATION IN GLACIATED TERRAIN, INCLUDING DATA FROM THE 2024 NEW JERSEY EARTHQUAKE: COLLABORATIVE RESEARCH WITH TUFTS UNIVERSITY AND MERRIMACK COLLEGEPROJECT PERIOD: 8 1 2025 THROUGH 7 31 2026AWARD PURPOSE: MACROSEISMIC INTENSITY RECORDINGS ARE AN UNDERUTILIZED SOURCE OF HIGH RESOLUTION, SITE-SPECIFIC DATA FOR SITE RESPONSE ASSESSMENT. INTENSITY PREDICTION EQUATIONS, WHICH PREDICT MODIFIED MERCALLI INTENSITY (MMI) FOR EARTHQUAKES, ARE AN IMPORTANT TOOL FOR REAL-TIME SEISMIC HAZARD ASSESSMENT AND INTERPRETATIONS OF SHAKING FROM HISTORIC AND RECENT EARTHQUAKES. THIS WORK WILL UTILIZE DID YOU FEEL IT? (DYFI) DATASETS IN THE CENTRAL AND EASTERN UNITED STATES (CEUS) TO VERIFY RECENTLY DEVELOPED SITE AND BASIN TERMS FOR THE REGION AND IMPROVE INTENSITY PREDICTION EQUATIONS. THE RECIPIENT WILL PAIR GEOSPATIAL DATA (WHICH PROVIDE BROAD SPATIAL COVERAGE OF SITE CHARACTERISTICS) WITH DYFI DATA (WHICH PROVIDE BROAD SPATIAL COVERAGE OF MACROSEISMIC INTENSITIES) TO DEVELOP SITE TERMS FOR INTENSITY PREDICTION EQUATIONS. FURTHER, WE HYPOTHESIZE THAT SPATIALLY RICH DYFI DATA CAN BE USED TO BETTER UNDERSTAND SITE AND BASIN EFFECTS DURING EARTHQUAKES, BECAUSE MACROSEISMIC INTENSITY DATA IS AVAILABLEAT SUCH A STRONGER SPATIAL RESOLUTION THAN TRADITIONAL GROUND-MOTION RECORDINGS.ACTIVITIES TO BE PERFORMED: FIRST, WE WILL COLLECT AND COMPILE ALL DYFI RESPONSES FROM 1999 TO 2024 IN THE PREVIOUSLY GLACIATED TERRAIN OF THE CEUS TO PRODUCE A MACROSEISMIC INTENSITY DATABASE. VARIABLES OF INTEREST INCLUDE THE REPORTED MODIFIED MERCALLI INTENSITY (MMI), HYPOCENTRAL DISTANCE, EPICENTRAL DISTANCE, NUMBER OF DYFI RESPONSES, POPULATION, EARTHQUAKE MAGNITUDE, EARTHQUAKE DATE, AS WELL AS SITE AND BASIN TERMS. SECOND, WE WILL USE THE ATKINSON ET AL. (2014) INTENSITY PREDICTION EQUATION TO PREDICT MMI FOR EACH 1 KM GRID SQUARE USING THE 2024 M 4.8 TEWKSBURY, NJ, EARTHQUAKE, AND COMPUTE RESIDUALS BETWEEN THE OBSERVED AND PREDICTED INTENSITIES. THESE EVENT-SPECIFIC RESIDUALS WILL BE EXAMINED TO SEARCH FOR HIGH-RESOLUTION SPATIAL TRENDS WITH THE PREVIOUSLY PROPOSED SITE TERMS. THE THIRD TASK WILL BE TO EXPAND THIS RESIDUAL ANALYSIS TO INCLUDE ALL DYFI DATA IN OUR MACROSEISMIC DATABASE, INCLUDING ANY REPORTS IN THE GLACIATED TERRAIN FROM 1999 TO 2024 IN THE GLACIATED TERRAIN. THE RECIPIENT WILL PERFORM LINEAR MIXED EFFECTS REGRESSION TO OBTAIN INTENSITY-BASED SITE-TO-SITE RESIDUAL TERMS.FINALLY, USING THE FULL MACROSEISMIC DATABASE AND CALCULATED RESIDUALS FROM THE RELEVANT EVENTS, THE RECIPIENT WILL USE RESIDUAL ANALYSIS TO EXAMINE HIGH-RESOLUTION, REPEATED, SITE-SPECIFIC EFFECTS. WE WILL COMPARE THESEINTENSITY-BASED SITE-TO-SITE RESIDUAL TERMS WITH OUR PROPOSED SPATIALLY CONTINUOUS SITE AND BASIN TERMSCREATED FROM SEDIMENT THICKNESS, WAVELET COEFFICIENT, AND SURFICIAL ROUGHNESS.DELIVERABLES AND EXPECTED OUTCOMES: THE DELIVERABLES OF THIS RESEARCH WILL BE: (A) A MACROSEISMIC DATABASE INCLUDING GEOSPATIAL AND GEOLOGY-BASED SITE TERMS, (B) RESIDUAL ANALYSIS FOR THE MACROSEISMIC DATABASE USING THE ATKINSON ET AL. (2014) INTENSITY PREDICTION EQUATION, AND (C) A NEW SITE TERM FOR USEIN INTENSITY PREDICTION EQUATIONS.INTENDED BENEFICIARIES: THIS PROJECT IS FOCUSED ON DID YOU FEEL IT? DATA IN CENTRAL AND EASTERN UNITED STATES, WITH A FOCUS ON PREVIOUSLY GLACIATED TERRAIN. THIS PROJECT WILL THEREFORE BENEFIT PUBLIC AGENCIES, STATE AGENCIES, FEDERAL AGENCIES, AND STAKEHOLDERS THAT ARE INTERESTED IN THE USGS GROUND MOTION PRODUCTS FOR THIS REGION. IN ADDITION, THIS PROJECT WILL IMPACT THE PROFESSIONAL DEVELOPMENT OF ONE GRADUATE STUDENT RESEARCHER AND ONE UNDERGRADUATE STUDENT RESEARCHER, AS WELL AS STUDENTS AT BOTH TUFTS UNIVERSITY AND MERRIMACK COLLEGE. WE ALSO INTEND TO WRITE AN ACCESSIBLE AND AVAILABLE ARTICLE OUTLINING OUR WORK WITH DYFI DATA TO ENCOURAGE PUBLIC EDUCATION AND ENGAGEMENT.SUBRECIPIENT ACTIVITIES: N A