Correlation of Non-Ergodic Path Effects for Intensity and Ground- Motion Data
Description:
Modified Mercalli Intensity (MMI) data has much denser spatial sampling than ground-motion data. Therefore, MMI data may provide better constraints on non-ergodic path effects than the available ground-motion data. We evaluate if the path effects for MMI data are consistent with the path effects for ground-motion data to determine if the MMI data will provide useful constraints on the non-ergodic ground-motion models (GMMs). For the MMI data, we selected records with intensity greater than four and rupture/hypocentral distances less than 200 km. The non-ergodic behavior is captured through the approach of Sung et al. (2023) which quantifies the anisotropic path effects due to the 3-D velocity structure using the varying coefficient model in an iterative process. In the first step, the spatially variable path term per site with the spatial correlation based on the separation between earthquakes is estimated. The second step uses the results of step 1 as the input to the new covariance function to calculate the spatial varying path terms and epistemic uncertainty for a specific source location for all site locations. The result shows that the path terms for MMI and short-period spectral accelerations have a high correlation, whereas the MMI and long-period ground motions have a lower correlation. Therefore, for short spectral periods, the non-ergodic path behavior from the MMI data may provide useful constraints on path terms for non-ergodic GMMs. A second issue is the magnitude-dependence of the non-ergodic path terms. The ground-motion data used for non-ergodic path terms is dominated by small-magnitude data. The MMI data from historic large-magnitude events that have few or no ground-motion data can be used to test the extrapolation of non-ergodic path terms to large-magnitude events.
Session: Advances in Probabilistic Seismic Hazard Analysis and Applications
Type: Oral
Date: 4/19/2023
Presentation Time: 10:45 AM (local time)
Presenting Author: Chih Hsuan Sung
Student Presenter: No
Invited Presentation:
Authors
Norman Abrahamson abrahamson@berkeley.edu University of California, Berkeley |
Chih Hsuan Sung Presenting Author Corresponding Author karensung@berkeley.edu University of California, Berkeley |
|
|
|
|
|
|
|
Correlation of Non-Ergodic Path Effects for Intensity and Ground- Motion Data
Category
Advances in Probabilistic Seismic Hazard Analysis and Applications