SZ4D Implementation Plan

Subduction Zones in Four Dimensions, or SZ4D, is a new community-driven, multi-decadal interdisciplinary scientific initiative that strives to understand how the different components of subduction zone systems interact to produce and magnify geohazards over time. It addresses major gaps in our understanding of geohazards by capitalizing on the availability of new observational, analytical, and computational techniques and by coordinating fundamental research on the physical and chemical characteristics and processes in subduction zones. Subduction zones provide the opportunity to strategically investigate integrated hazards simultaneously and conduct well-controlled natural experiments that can be used to isolate and study key factors that drive geohazards. A cornerstone of SZ4D is bringing together scientists with a diverse range of geoscience backgrounds and skill sets who study earthquakes, volcanic eruptions, and surface processes.

Earth’s principal geohazards are concentrated in subduction zones, locations where one tectonic plate slides beneath another. Earthquakes and tsunamis can cause devastation on enormous scales, disrupting entire societies. Large volcanic eruptions have repeatedly destroyed cities and altered weather patterns throughout human history, resulting in crop failures, famines, and population decline and migration. Landslides, debris flows, and floods have erased mountain towns and villages, disrupted agriculture, severed transportation routes, and profoundly affected urban and rural populations alike. Despite the global ambition to forecast these geohazards, we have only limited understanding of the complex physical and chemical processes that interact to trigger earthquakes, tsunamis, and volcanic eruptions. We also have limited understanding of the many ways in which these geohazards are linked to Earth surface processes such as sediment erosion and deposition.

To date, progress in understanding the potential predictability of geohazards has not only been limited by persistent knowledge gaps, it has been hampered by studies that have historically been conducted within disciplinary boundaries. Yet, there are obvious, shared crosscutting themes that link subduction zone studies, suggesting an interdisciplinary approach would significantly advance the science.

This document provides the details of how the scientific community will implement SZ4D over the initiative’s decadal lifespan. It describes the observational, experimental, and numerical components required to capture the range of spatial and temporal scales over which subduction zone processes operate and the significant and sustained investment in human and physical infrastructure needed to support this effort. Using a collective impact model, scientists will closely coordinate their research across disciplines and will leverage existing efforts so that new activities build on the scaffolding of past successes. To enable close integration and phasing within and between components of this implementation plan, a center will coordinate deployment of instrumental and human resources, while individual investigators will also be empowered to be creative through a dedicated SZ4D science program. With the involvement of a diverse community of scientists and stakeholders in this SZ4D effort, we are poised to make a major leap forward in our understanding of subduction zone hazards for the benefit of society.