1. Introduction

This online ShakeMap Manual (Worden et al., 2020), is for ShakeMap version 4. Version 4 is the official, supported version of ShakeMap and all earlier versions are now deprecated. This manual supersedes all other versions of the ShakeMap Manual, including the ShakeMap 3.5 Manual (both printed and online) and the USGS Techniques and Methods document (508)12-A1.

ShakeMap®, developed by the U.S. Geological Survey (USGS), facilitates communication of earthquake information beyond just magnitude and location. By rapidly mapping out earthquake ground motions, ShakeMap portrays the distribution and severity of shaking. This information is critical for gauging the extent of the areas affected, determining which areas are potentially hardest hit, and allowing for rapid estimation of losses. Key to ShakeMap’s success, algorithms were developed that take advantage of any high-quality recorded ground motions—and any available macroseismic intensity data—to provide ground-truth constraints on shaking. Yet ShakeMap also utilizes best practices for both interpolating recordings and—critically—providing event-specific estimates of shaking in areas where observations are sparse or nonexistent. Thus, ShakeMap portrays the best possible description of shaking by employing a combination of recorded and estimated shaking values.

This Manual provides background on technical aspects of ShakeMap including: 1) information on the wide range of products and formats ShakeMap produces, 2) the uses of these products, and 3) guidance for ShakeMap developers and operators.

Readers interested in understanding the way ShakeMaps works can navigate to the Technical Guide. Those who want to use ShakeMap products and understand their varied forms can jump to the User’s Guide. The Software Guide provides information on the software architecture, installation and configuration, and operational considerations for those wishing to run a regional ShakeMap system.

To cite this manual:

Worden, C.B., E. M. Thompson, M. Hearne, and D.J. Wald (2020). ShakeMap Manual Online: technical manual, user’s guide, and software guide, U. S. Geological Survey. http://cbworden.github.io/shakemap/. DOI: https://doi.org/10.5066/F7D21VPQ.