Operational Earthquake Forecasting State of Knowledge and Guidelines for Utilization Report by the International Commission on Earthquake Forecasting for Civil Protection Submitted to the Department of Civil Protection, Rome, Italy 20 March 2011 International Commission on Earthquake Forecasting for Civil Protection Thomas H. Jordan, Chair of the Commission Director of the Southern California Earthquake Center; Professor of Earth Sciences, University of Southern California, Los Angeles, USA Yun-Tai Chen Professor and Honorary Director, Institute of Geophysics, China Earthquake Administration, Beijing, China Paolo Gasparini, Secretary of the Commission President of the AMRA (Analisi e Monitoraggio del Rischio Ambientale) Scarl; Professor of Geophysics, University of Napoli “Federico II”, Napoli, Italy Raul Madariaga Professor at Department of Earth, Oceans and Atmosphere, Ecole Normale Superieure, Paris, France Ian Main Professor of Seismology and Rock Physics, University of Edinburgh, United Kingdom Warner Marzocchi Chief Scientist, Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy Gerassimos Papadopoulos Research Director, Institute of Geodynamics, National Observatory of Athens, Athens, Greece Gennady Sobolev Professor and Head Seismological Department, Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia Koshun Yamaoka Professor and Director, Research Center for Seismology, Volcanology and Disaster Mitigation, Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan Jochen Zschau Director, Department of Physics of the Earth, Helmholtz Center, GFZ, German Research Centers for Geosciences, Potsdam, Germany Preface This report by the International Commission of Earthquake Forecasting for Civil Protection responds to a request from the Italian government to assess the scientific knowledge of earthquake predictability and provide guidelines for the implementation of operational earthquake forecasting. As defined here, “operational forecasting” involves two key activities: the continual updating of authoritative information about the future occurrence of potentially damaging earthquakes, and the officially sanctioned dissemination of this information to enhance earthquake preparedness in threatened communities. Although considerable research is being devoted to the science of short-term earthquake forecasting, the standardization of operational procedures is in a nascent stage of development. The problem is challenging because large earthquakes cannot be reliably predicted for specific regions over time scales less than decades. Therefore, short-term forecasts of such events never project high probabilities, and their incremental benefits for civil protection—e.g., relative to long-term seismic hazard analysis—have not been convincingly demonstrated. Under these circumstances, governmental agencies with statutory responsibilities for earthquake forecasting have been cautious in developing operational capabilities of the sort described in this report. Nevertheless, public expectations that any valid information about enhanced seismic risk will be made available and effectively utilized are clearly rising. Experience shows that information vacuums can spawn informal predictions and misinformation, and that relying solely on informal communications between scientists and the public invites confusion. In this context, the deployment of systematic and transparent procedures for operational earthquake forecasting must be seriously considered. Italian earthquake experts are in the forefront of the research needed for the implementation of operational earthquake forecasting. This report highlights their accomplishments and provides a roadmap for building upon their current efforts. While written for this purpose, the Commission hopes that its study will be useful not only in Italy, but also in other seismically active regions where operational earthquake forecasting may be warranted. The report was written prior to the damaging aftershock of 22 February 2011 in Christchurch, New Zealand, and the catastrophic Tohoku earthquake of 11 March 2011 off the Pacific coast of Japan, and no attempt was made to revise its content in the light of these events. However, they underline the need for authoritative information about time-dependent seismic hazards, especially in the wake of major earthquakes, and their implications, as currently understood, do not contradict the Commission’s findings and recommendations. Many scientists in a number of countries have contributed to the report, and the Commission is grateful for their help. The report was improved by a number of peer reviews, and we are grateful for their recommendations. Prof. Paolo Capuano of the University of Salerno deserves a special word of thanks for his assistance to the Commission in all aspects of its work, including meeting arrangements, report preparations, and a special website that enhanced its internal correspondence. The Commission would also like to recognize the generous support of the Italian Department of Civil Protection, especially the encouragement of Dr. Guido Bertolaso and Prof. Mauro Dolce. Thomas H. Jordan Commission Chair Table of Contents Abstract......................................................................................................................................... 1 I. Introduction ............................................................................................................................. 2 A. Charge to the Commission ..............................................................................................................2 B. L’Aquila Earthquake ........................................................................................................................2 C. Conduct of the Study .......................................................................................................................5 D. Organization of the Report ..............................................................................................................6 II. Science of Earthquake Forecasting and Prediction ................................................................ 7 A. Definitions and Concepts.................................................................................................................7 B. Research on Earthquake Predictability .........................................................................................12 C. Predictability of Fault Interaction ...................................................................................................22 D. Probabilistic Forecasting Models...................................................................................................24 E. Validation of Earthquake Forecasting Methods.............................................................................30 III. Status of Operational Earthquake Forecasting ..................................................................... 35 A. China (Chen) .................................................................................................................................35 B. Greece (Papadopoulos) ................................................................................................................36 C. Italy (Marzocchi & Gasparini) ........................................................................................................38 D. Japan (Yamaoka) ..........................................................................................................................39 E. Russia (Sobolev) ...........................................................................................................................41 F. United States (Jordan)...................................................................................................................42 G. Summary and Discussion..............................................................................................................45 IV. Key Findings and Recommendations ................................................................................... 46 A. Need for Probabilistic Earthquake Forecasting .............................................................................46 B. Earthquake Monitoring ..................................................................................................................46 C. Research on Earthquake Predictability .........................................................................................47 D. Development of Long-Term Forecasting Models ..........................................................................47 E. Development of Short-Term Forecasting Models..........................................................................48 F. Validation of Earthquake Forecasting Methods.............................................................................48 G. Utilization of Earthquake Forecasts...............................................................................................49 H. Public Communication of Earthquake Information ........................................................................49 V. Roadmap for Implementation................................................................................................ 51 A. Underway ......................................................................................................................................51 B. Outstanding Actions ......................................................................................................................51