1.1. Purpose

This report presents a plan supported by the National Earthquake Hazards Reduction Program (NEHRP) to coordinate domestic and international post-earthquake investigations (herein called “the Plan”). The Plan describes the activation and coordination of the four designated NEHRP Agencies in the Federal Government:

The Plan also describes coordination between NEHRP Agencies and other organizations that participate in pre-event and post-earthquake investigations. They may include non-NEHRP Federal agencies; State, regional, local, Tribal, and territorial agencies; domestic nongovernmental organizations; academic institutions and affiliated organizations; private companies; foreign governmental agencies and nongovernmental organizations; and international organizations.

NEHRP is the Federal Government’s coordinated nationwide program to reduce risks to life and property in the United States, U.S. territories, and federally recognized Tribal Nations (all herein included in the “United States”) that result from earthquakes. The Earthquake Hazards Reduction Act of 1977 (Public Law 95–124), as amended by the National Earthquake Hazards Reduction Program Reauthorization Act of 2018 (Public Law 115–307) (herein called “the Act”), authorizes the investigation of significant domestic and international earthquakes to learn lessons that can be applied to reduce future earthquake losses in the United States. The Act states that the investigations shall begin as rapidly as possible and results shall be disseminated widely.

The Act also specifically directs the USGS to organize post-earthquake investigations to study the implications of earthquakes in the responsibility areas of each of the four NEHRP Agencies and to utilize expertise of other Federal agencies and private contractors. Thus, the USGS is the lead NEHRP Agency for activating and coordinating NEHRP post-earthquake investigations and for implementing this Plan. The Plan does not preclude any of the four NEHRP Agencies from studying the implications of earthquakes, domestic or international, within the areas of their own responsibilities and outside the scope of this Plan.

In addition to delineating the coordination of NEHRP post-earthquake investigations, the Plan identifies pre-event activities necessary to ensure that post-earthquake investigations are executed effectively. The USGS also leads coordination of the NEHRP Agencies in completing the pre-event activities identified in the Plan.

The Plan should be viewed as guidance for pre-event and post-earthquake activities to be undertaken by NEHRP Agencies depending upon their available resources and priorities.

Additional background information, a description of the development process for the Plan, and a list of project participants are contained in appendix A. The responsibilities of the NEHRP Agencies as enumerated by the Act are presented in appendix B.

1.2. Achieving an Earthquake-Resilient Nation

The United States must be ready and capable to withstand, respond to, and recover from earthquakes and their consequences. The strategic goals and objectives in the NEHRP Strategic Plan (NIST, 2023) describe how the United States enhances its resilience and security against earthquake effects by developing, advancing, and disseminating knowledge, tools, practices, and policies.

Post-earthquake investigations should be coordinated to maximize learning and to translate lessons quickly and effectively into practices that mitigate the effects of future earthquakes. Experience has demonstrated that post-earthquake investigations can substantially further the achievement of the following goals:

Achieving a more resilient Nation demands that we understand what happens to the built environment and to society when an impactful earthquake occurs. Documenting and sharing the key lessons learned from earthquakes worldwide contribute significantly to advancing the understanding of earthquake processes and their effects. Earthquakes provide critical information, and many engineering design procedures and community response plans are based on insights gleaned from the observations of past events. Field observations are particularly important because it is difficult to replicate in the laboratory geologic features built by nature over millions of years; interdependencies of large-scale infrastructure systems; the seismic performance of large inventories of buildings; the impacts of cascading, compounding, and co-occurring events, such as tsunamis, landslides, or fire-following earthquake; and the behavior of people confronted by death and destruction.

Coordination of multidisciplinary and interdisciplinary research efforts following earthquakes can enhance the information acquired and its dissemination. The nature and quality of this information can significantly reduce losses from future events through improved planning, design, and construction. Because many of the data generated by earthquakes are perishable, organizations should be prepared to respond in a timely and sustained manner to collect observational data describing what happens when earthquakes strike.

Domestic earthquakes provide the best opportunity to evaluate seismic hazards, the performance of the built environment, and the effects on the socioeconomic environment in the United States, where lessons learned can be implemented directly. International earthquakes can also provide valuable learning opportunities. They often affect geologic environments similar to those in the United States, which can provide knowledge to advance U.S. geoscience and geotechnical engineering. Because building codes and practices in some countries are similar to U.S. codes and practices, insights on building and lifeline performance in international earthquakes can directly inform future U.S. codes and practices. And insights gleaned from social science research abroad are often relevant to the United States.

However, conducting investigations in foreign countries often presents challenges that are not present for domestic investigations. For example, investigations in foreign countries greatly benefit from, perhaps even require, collaboration with local agencies to be effective; proficiency in languages other than English may be necessary; and travel can be more restricted than it is in the United States. Consequently, the Plan has descriptions of different responses to domestic earthquakes and international earthquakes.

2.1. Plan Structure and Phases

The main purpose of the Plan is to facilitate the activation and coordination of NEHRP post-earthquake investigations. The decision to undertake a NEHRP post-earthquake investigation is primarily based on whether an earthquake presents an important opportunity to learn lessons that can reduce the loss of lives and property in future earthquakes. Thus, the specific criteria for activation considered by the NEHRP Agencies are likely to evolve over time and will be informed by critical gaps in research and practice that are needed to achieve seismic resilience. NEHRP Agencies should retain flexibility to activate post-earthquake investigations when important opportunities that may not have been previously identified arise following an earthquake.

This Plan describes the response for various levels of earthquake impacts, both domestic and international, indicates which actions are part of the coordinated response of NEHRP Agencies, and designates actions that may be taken for international earthquakes. More details on the criteria for activating implementation of the Plan following an earthquake are provided in section 3.0. Individual NEHRP Agencies may also study the implications of earthquakes within the areas of their own responsibilities and outside the scope of this Plan.

The Plan has post-earthquake investigations organized into three phases:

The event-specific activities related to each phase are provided in sections 4.0 through 6.0. A flow chart of the phases and key activities addressed in the Plan is shown in figure 1.

2.2. Key Participants in the Plan

The work of NEHRP is coordinated at the highest level by the Interagency Coordinating Committee (ICC) on Earthquake Hazards Reduction and at the working level by the Program Coordination Working Group (PCWG). The ICC is chaired by the NIST Director and includes the Administrator of FEMA and the Directors of the U.S. National Science Foundation, the Office of Management and Budget, the Office of Science and Technology Policy, and the U.S. Geological Survey. The PCWG has designated representatives from each of the NEHRP Agencies who meet regularly to report on individual Agency activities and coordinate program efforts, including budget reporting and strategic planning.

The USGS, acting through its Earthquake Hazards Program (EHP) is the lead Agency for activating and coordinating NEHRP post-earthquake investigations and calls upon the PCWG to help the USGS fulfill its responsibilities as Investigation Coordinator under the law and to lead pre-event and post-earthquake coordination activities on behalf of NEHRP as specified in the Plan. The PCWG can be a nexus through which NEHRP coordination is managed.

Following an earthquake, the PCWG may appoint an ad hoc Earthquake Investigations Committee (EIC) to carry out the day-to-day coordination, or the PCWG may choose to serve in this capacity itself; to include these options, the PCWG-EIC is designated in the Plan as the main coordinating body. The PCWG-EIC should include at least one representative from each of the NEHRP Agencies. The representative from the USGS will serve as the committee chair and lead the investigations coordination. The PCWG-EIC is discussed further in section 4.0.

For pre-event and post-earthquake investigations to be effective, the NEHRP Agencies may coordinate with other organizations, as described in the Plan. As mentioned in section 1.1, other potential partners include non-NEHRP Federal agencies; State, regional, local, Tribal, and territorial agencies; domestic nongovernmental organizations; academic institutions and affiliated organizations; private companies; foreign governmental agencies and nongovernmental organizations; and international organizations (fig. 2). Potential partnering organizations should evolve over time and be informed by advances in technology, programs, and policy, as well as by research and practice on achieving seismic resilience. Additional information about potential partnering organizations is presented in appendix C and appendix D.

2.3. Pre-Event Activities

Advance planning helps ensure that the Plan and potential partners are ready for post-earthquake activation. The following pre-event activities are recommended for the PCWG for both domestic and international earthquakes.

In addition, the USGS, with support from the PCWG, should work to ensure that the activation, coordination, and overall objectives of NEHRP post-earthquake investigations help to facilitate disaster response and recovery operations. These objectives should align with the “National Response Framework” (NRF) from FEMA (2019b) and the “National Disaster Recovery Framework” (NDRF), also from FEMA (2016). Both frameworks define the Federal role in response to all types of disasters and emergencies and in enabling effective recovery support to disaster-impacted States and local, Tribal, and territorial jurisdictions. Appendix E provides additional information on both frameworks.

2.4. Testing and Exercising the Plan

As part of its coordination role, the USGS, with support from the PCWG, should develop and conduct exercises and training sessions on the Plan to test it against realistic earthquake scenarios and promote Plan awareness, working knowledge, and coordination among NEHRP Agencies, potential partners, and other stakeholders. Exercises and training sessions may vary in style and levels of participation, be held remotely or in person, and include the following:

An exercise should be conducted within 1 year of completion of the Plan and at least once every 3 years thereafter, or as needed to ensure that PCWG representatives are prepared to launch and support post-earthquake investigations whenever needed. Organizers choosing dates and locations for exercises may consider timing and coordination opportunities with NEHRP Agencies, professional association meetings, and earthquake-response exercises hosted by Federal, State, and local emergency management agencies and regional earthquake consortia.

Realistic earthquake scenarios should vary in earthquake intensity, geographic coverage across different regions of the United States, stakeholders engaged, and scale and consequences of earthquake impacts and data-gathering needs; scenarios may include compounding and cascading earthquake disasters involving other natural and technological hazards, and co-occurrences of tsunamis, fire-following earthquake, and other events. These exercises and their results can be recorded as playbooks to be referenced by the PCWG and key agencies when actual earthquakes with similar characteristics occur.

Exercises and training will include training on safety and the ethical procedures and protocols of post-earthquake investigations and other activities defined by the Plan. Exercise and training evaluations should assess (1) if actions identified in the Plan were effectively implemented during the exercise, (2) if the contents of the Plan need revision, and (3) if the engagement and performance of all participants led to positive results.

Finally, ensuring Plan readiness means that there should be live, online access for relevant parties to the Plan document at all times, with any amendments also available as they occur. The USGS and other NEHRP Agencies should be mindful of staffing changes and the need to familiarize new representatives with Agency responsibilities under the Plan.

2.5. Reviewing and Updating the Plan

Given the relative infrequency of damaging earthquakes in the United States, it is important that the Plan be reviewed regularly. The PCWG leads the process of reviewing and amending the plan, as needed:

All NEHRP Agencies, key partners, and a broad array of stakeholders should be involved in the review, including members of the professional and research communities.

3.1. Descriptions of Earthquakes in the Plan

Information on the impact of an earthquake is obtained from sources listed below:

Earthquake levels for the Plan are assigned on the basis of initial data. The NEHRP Agencies may adjust the level of an earthquake after considering information in addition to that provided by PAGER or the other sources listed above. Levels are defined below:

3.2. Earthquake Notification and Plan Activation

Upon receiving notification of a potentially significant earthquake event regardless of location, the PCWG should consider whether a NEHRP post-earthquake investigation may be appropriate through the following actions:

4.1. Reconnaissance Planning and Initial Communication

The first phase of the post-earthquake investigation is dedicated to Plan activation, initial communication, and emergency response support. The following recommended Phase 1 steps apply to all sizes of earthquakes regardless of location when the Plan is activated by the PCWG.

4.2. Technical Clearinghouse

A Technical Clearinghouse is a mechanism for coordinating and facilitating post-earthquake field communication and for sharing observations and knowledge among organizations participating in post-earthquake investigations.

It is crucial that emergency response activities are not impeded by scientific and engineering investigations, and it is important that response and recovery managers, notably emergency managers and building officials, are provided with timely and relevant information from ongoing investigations. To meet these goals, direct communication needs to be established and maintained between the Technical Clearinghouse and Federal and State coordinating officers designated for a particular earthquake.

4.3. Event Communication

Event communication, which primarily should be disseminated using the event page, serves to provide centralized, publicly available information related to ongoing investigations, preliminary findings, and funding opportunities through up-to-date links to other sites. It is intended to provide information to academic researchers, policymakers, professional communities, and the interested public who are not involved in the investigations process. It is not intended as a means for research coordination or a data repository.

4.4. International Investigators

If a domestic earthquake is significant and receives prominent coverage by the news media, international researchers are likely to come to the United States to investigate the earthquake. Where appropriate, international researchers should be encouraged to partner with U.S. researchers and engage in the Technical Clearinghouse coordination activities.

Partnerships between U.S. and international researchers can be mutually beneficial. They can increase the number of people and resources involved in investigations; provide opportunities for joint data collection, sharing, and publishing; and help foster consistent messaging about the causes and consequences of disasters. In some cases, it may be appropriate to develop formal agreements between U.S. agencies and partner international agencies.

5.1. Data-Gathering Principles

The main goal of data gathering is to collect perishable observations of the earthquake effects that can be used to understand the broader impacts of the event, inform hazard mitigation, and enable future research efforts that address the strategic goals and objectives delineated in the NEHRP Strategic Plan (NIST, 2023) and enhance the Nation’s resilience and security against earthquakes. Earthquake effects include the direct, indirect, and cascading physical and societal impacts of fault rupture and ground shaking hazards, as well as secondary hazards such as landslides, liquefaction, fire-following earthquakes, and tsunamis.

Observations that inform our understanding of the earthquake will come from the field, but increasingly more information is being gathered from online resources (such as social media, citizen scientists) and new technologies (such as satellite imagery). These observations may be broadly categorized within geoscience, engineering, and social science disciplines.

The disciplinary data collection described in the next sections encompasses a broad range of activities. Most of these activities may be undertaken following a Level 1 domestic earthquake, but only a subset may be undertaken following a Level 2 or Level 3 domestic earthquake or a significant international earthquake. For Level 1 domestic earthquakes, there should also be a special focus on interdisciplinary collaboration among the different data-gathering disciplines. The types and scope of Phase 2 activities will likely evolve over the course of the investigation.

In collecting data after an earthquake, several overarching principles should be followed:

5.2. Geoscience Data Collection

The goals of earth geoscience data collection are to investigate seismic sources and aftershocks and document fragile and perishable primary and secondary earthquake effects. The entities involved in geoscience data collection generally will include USGS, NSF-supported and other academic researchers, NIST, NOAA (for tsunamigenic earthquakes), and the National Aeronautics and Space Administration (NASA).

The geoscience response will focus on complete mapping and documentation of ground rupture, deformation, and ground failures, including areas where deformation and failures did not occur. Seismic and geodetic data collection will capture mainshock and foreshock characteristics, aftershock sequences, and ground motions to illuminate the relationships among mainshock slip characteristics, aftershock occurrence, and site response.

The objective is to collect a complete set of field observations for testing predictive models of earthquake rupture and ground response. This set will help researchers to improve future seismic hazard mapping and to discern the interplay among ground shaking, geology, geomorphology, and various types of damage and failure in both the natural and built environments.

The types of data collections listed below are not intended to be exhaustive and are listed as suggestions for typical post-earthquake research.

5.3. Engineering Data Collection

Collection of engineering data immediately after an earthquake involves observation and documentation of both detected damage and the lack thereof. The main goal of data collection is to advance empirical methodologies and state-of-practice analyses, which ultimately lead to improved engineering codes, standards, and guidelines. The engineering data-gathering needs for geotechnical systems, buildings, and lifelines are discussed separately below.

5.4. Social Science Data Collection

During social science investigations following earthquakes, researchers consider aspects of human behavior, decision making under uncertainty, policy, and socioeconomic relationships, especially as connected to the built and natural environments. The social sciences involve many unique disciplines, including anthropology, economics, geography, planning, political science, psychology, public administration, public health, and sociology, among others. The entities involved in social science data collection are broad and will include EERI and NSF-funded and other academic researchers, among others.

The data that social scientists collect are diverse and can involve qualitative, quantitative, and mixed methods approaches to gathering data. This may involve, for example, surveys, interviews, observations, or the analysis of secondary data. As applicable, timestamping, geotagging, social science identifiers, and other data-collection best practices should be part of investigation protocols and procedures.

Social science priorities for data collection in the immediate and longer term aftermath of an event may focus on a range of issues that rapidly evolve based on community- and societal-level impacts. For example, social scientists may study any of the following topics:

This list is not meant to be exhaustive but instead indicative of the range and types of issues that social scientists may study and that may be influenced by the status of the built environment.

Post-earthquake socioeconomic investigations often include research involving human subjects and the collection of personally identifiable information (PII) and other sensitive information. McCallister and others (2010, p. 2–1) identified PII broadly as “any information about an individual maintained by an agency, including (1) any information that can be used to distinguish or trace an individual’s identity, such as name, social security number, date and place of birth, mother’s maiden name, or biometric records; and (2) any other information that is linked or linkable to an individual, such as medical, educational, financial, and employment information.”

It is crucial that social science teams—as well as geoscience and engineering teams—adhere to ethical standards in data gathering and employ appropriate approaches for storing and sharing protected data. Social science investigators should comply with the procedures approved by their respective IRBs and data protections specified in the Family Educational Rights and Privacy Act of 1974 (Public Law 93–380), the Privacy Act of 1974 (Public Law 93–579), the Paperwork Reduction Act of 1980 (Public Law 96–511), and the Health Insurance Portability and Accountability Act of 1996 (Public Law 104–191), as applicable.

5.5. Data Sharing, Publishing, and Archiving

Data sharing during Phase 2 is focused on providing access to data products (such as reports, spreadsheets, image files, maps) collected by field teams or virtual reconnaissance teams. Online access to these data products may take advantage of existing online cloud storage resources provided by the Technical Clearinghouse. It may be appropriate for the Technical Clearinghouse to delegate coordination of data uploads to a single person, a data integrator (section 4.2.4.e), who is familiar with online resources. It will be useful to interact with data-sharing portals (for example, FEMA Geospatial Resource Center, the NSF-supported DesignSafe facility) associated with the NEHRP Agencies, as well as with portals created or supported by non-NEHRP Federal agencies, such as NASA. Other geographic information system (GIS)-enabled data sharing (commonly discipline specific) may be utilized, if available.

It is anticipated that most of the datasets collected during Phase 2 reconnaissance activities ultimately will be published formally in a stable, online data repository with an assigned Digital Object Identifier (DOI). Data publishing will allow the collected data to be used and reused by the broader research community. Individual reconnaissance teams will be responsible for curating and publishing their data in an appropriate data repository. Researchers may choose to publish their data in repositories that are specific to a technical domain (for example, USGS ScienceBase for geoscience data, DesignSafe Data Depot for natural hazards engineering and social science data) or in repositories that are open to any type of data (for example, Zenodo). The selected data repository should offer long-term archiving and follow FAIR (Findable, Accessible, Interoperable, Reusable) data principles.

6.1. Event Page

This Plan identifies the online event page as the starting point for public-facing information dissemination following an earthquake. The page should be updated with documents and relevant information as approved by the PCWG-EIC. Documents and information maintained, mirrored, or linked on the event page will serve as the basis for later event reports and summaries. The page should be available to the scientific and engineering communities and the broader public in perpetuity.

6.2. Priorities Workshop

Establishing priorities for long-term investigations, development, and implementation strategies following a major earthquake is an important role for NEHRP. Large damaging earthquakes typically provide many opportunities to improve our understanding of seismic events and their impacts. NEHRP Agencies, State agencies, and multistate consortia could jointly sponsor a workshop, which could be held virtually or in a hybrid fashion. Geoscientists, engineers, social scientists, and others involved in and with an interest in post-earthquake investigations should be invited to participate.

When evaluating investigation priorities, workshop attendees should focus on applicable local and State hazard mitigation and recovery initiatives and opportunities for multidisciplinary and interdisciplinary research. Results from the workshop can help ensure that NEHRP Agency funding decisions and written agreements are issued as quickly as possible following earthquakes. The PCWG-EIC may issue a workshop report identifying short- and long-term research needs and opportunities, with a list of recommended funding priorities.

6.3. Event Summary

The event summary, which should be made available as a link on the event page, is intended as a multidisciplinary and interdisciplinary document aimed at a general and broad audience and should cover geosciences, engineering, and social sciences. This proposed new product is not intended to substitute for institutional reports, such as EERI reconnaissance reports, USGS circulars, or reports by other organizations, that currently are produced following significant earthquakes.

The event summary should be widely accessible and serve as a definitive summary for key statistics and observations. The summary should be well illustrated and comprehensive and should integrate preliminary observations on the seismological processes controlling the event and impacts on the natural, built, and socioeconomic environments. Various formats could be used for event summaries. Preliminary information was used to create a prototype of an event summary on a USGS web page (Schmitt and others, 2024).

It is recommended that the event summary be prepared within 3 months to 1 year after the event and be linked to the event page. The contributions of major scientific and engineering investigative efforts supported under NEHRP should be integrated and incorporated. The PCWG-EIC should designate editors and co-editors from contributing organizations to facilitate broad participation.

6.4. After-Action Report

The USGS, in coordination with the PCWG-EIC, should lead the development of a brief after-action report that describes how the Plan was implemented, what worked well and what could be improved in its implementation, and recommended changes to the Plan.

6.5. Conferences and Events

There may be a need from about 6 months to 5 years following an earthquake for conferences or events focused on disseminating reconnaissance and earthquake findings and lessons learned to various audiences. The PCWG-EIC should consider events for various stakeholders, from technical experts to government policymakers, who will benefit from research and technology transfer. These events, which may be virtual or hybrid, should leverage and align with significant earthquake milestones or existing conferences that target the desired audiences. Findings may be shared as focused activities at existing events to leverage costs or at standalone events when appropriate.

6.6. Integrative Special Publication

An overarching goal of post-earthquake investigations is the preparation of an in-depth set of reports that synthesize the findings from reconnaissance and detailed studies carried out by research and professional-practice communities. For instance, the USGS published a series of six papers detailing the results of investigations of the 1964 Alaska earthquake (Hansen and others, 1966). However, these publications are costly to produce and take a considerable amount of time in production and publication. More recently, earthquake response syntheses have been collections of papers published in special volumes in peer-reviewed journals, such as the “Bulletin of the Seismological Society of America” and EERI’s “Earthquake Spectra.” These volumes are an efficient route to disseminate investigation summaries in a timely fashion.

Within 2 to 5 years following a significant domestic earthquake, an in-depth report consisting of one or more volumes should bring together relevant data in a concise fashion and emphasize the significant contributions of post-earthquake investigations to the knowledge base on earthquakes and earthquake-loss reduction. The publication should contain overviews of important findings derived from scientific and engineering research. This synthesis should include an extensive bibliography of post-earthquake reports and should focus on damage and disruption, as well as on situations where the built environment performed well and little or no damage occurred. A thorough synthesis is valuable for researchers and practitioners in that it provides both rapid entry into the literature on the earthquake and an overview of studies that have been conducted in different disciplines. A synthesis also distills significant lessons learned for future research, practice, and loss-reduction policy. The PCWG-EIC should share the special publication with research and practice communities using the event page and other mechanisms.

6.7. Long-Term Studies

The geoscience, engineering, and socioeconomic aspects of earthquake impacts and recovery will evolve over time, possibly on the order of years to decades. The PCWG-EIC should encourage long-term studies as one way to gage the total effects of earthquakes. Due to the long-term nature of these studies, workshops may be held and reports issued on a periodic basis, or results summarized in a detailed report at the end of the studies, with links to the studies eventually added to the event page. Membership on the PCWG may evolve as these studies are conducted, so incoming PCWG members should be briefed on any ongoing studies and the need to continue to fund them as appropriate.