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Developing and Implementing an International Macroseismic Scale (IMS) for Earthquake Engineering, Earthquake Science, and Rapid Damage Assessment

Description: 

Macroseismology plays a crucial role in earthquake hazard and risk analyses, tying earthquake occurrences and impacts from the past with those of the present and future. In fact, the use of macroseismic intensity has grown recently as the hazard layer within essential USGS and others’ real-time earthquake information products, including Earthquake Early Warning, ShakeMap, “Did You Feel It?” (DYFI), PAGER, and even in presenting probabilistic seismic hazard maps in a friendlier format to nontechnical users. However, even with best practices, there are several limitations to modern macroseismic data collection approaches. First, whereas crowd-sourced intensities such as DYFI are robust and definitive for lower intensities, they are poorly defined above intensity VII, where damage observations require expert knowledge of each building’s structural system. Second, the United States, New Zealand, and others employ the Modified Mercalli Intensity (MMI) scale, which is consistent with—yet inferior to—the more recently developed European Macroseismic Scale (EMS-98). We report on an IMS Working Group meeting held in October 2022 at the USGS Powell Center to address these issues and to work towards an IMS. The workshop goals were, first, to harmonize the MMI scale with EMS-98 for the US and NZ—which share several similar building types—by considering those structures and associated damage grades not well represented in the current EMS-98 building vulnerability table. Second, formalize the process of augmenting EMS-98 with additional building classes and damage grades in other countries, thus promoting the development of a scale that can be used globally. Such efforts require reviewing and expanding the original EMS-98 explanatory documents and considering potential revisions. Finally, we discuss how standardized earthquake-damage data worldwide collection as part of genuine IMS could help facilitate earthquake hazard and engineering analyses.

Session: ShakeMap-related Research, Development, Operations, Applications and Uses

Type: Oral

Date: 4/19/2023

Presentation Time: 04:45 PM (local time)

Presenting Author: David J. Wald

Student Presenter: No

Invited Presentation: 

Authors