OPERATIONAL EARTHQUAKE FORECASTING. State of Knowledge and Guidelines for Utilization

Abstract

Operational earthquake forecasting comprises procedures for gathering and disseminating authoritative information about the time dependence of seismic hazards to help communities prepare for potentially destructive earthquakes. Seismic hazards are known to change with time, in part because earthquakes release energy and suddenly alter the conditions within fault systems that will lead to future earthquakes. Statistical and physical models of earthquake interactions have begun to capture many features of natural seismicity, such as aftershock triggering and the clustering of seismic sequences. These models can be used to estimate future earthquake probabilities conditional on a region's earthquake history.At the present time, earthquake probabilities derived from validated models are too low for precise short-term predictions of when and where big quakes will strike; consequently, no schemes for "deterministic" earthquake prediction have been qualified for operational purposes. However, the methods of probabilistic earthquake forecasting are improving in reliability and skill, and they can provide time-dependent hazard information potentially useful in reducing earthquake losses and enhancing community preparedness and resilience.This report summarizes the current capabilities of probabilistic earthquake forecasting in Italy and elsewhere. It offers recommendations about how to validate and improve operational forecasting procedures and how to increase their utility in civil protection. A. Charge to the CommissionThe International Commission on Earthquake Forecasting for Civil Protection ("the Commission" or ICEF) was authorized by Article 6 of Ordinanza del Presidente del Consiglio dei Ministri no. 3757, issued on 21 April 2009. The Commission was appointed by Dr. Guido Bertolaso, head of the Dipartimento della Protezione Civile (DPC), with the following statement of charge:1. Report on the current state of knowledge of short-term prediction and forecasting of tectonic earthquakes.

Long-term magnetic anomalies and their possible relationship to the latest greater Chilean earthquakes in the context of the seismo-electromagnetic theory

“…Under this concept, the anomalies correspond to the manifestation of the crack or microcrack within the lithosphere which allows the flux of electrical current due to the Zener-Stroh mechanism (e.g., Stroh, 1955;Ma et al, 2011), while changes in the seismicity rate are due to changes in the b value (Venegas-Aravena et al, 2020) which could generate seismic foreshock or slow slips as in Iquique 2014 (e.g., Herman et al, 2016). Also, this theory considers the main earthquake a crack that releases seismic energy as coseismic magnetic signals (Kanamori, 1977;Utada et al, 2011). The temporal evolution of these cracks and its relation to the sigmoidal magnetic anomalies' behavior can be seen in Fig.…”

Earth electricity: a review of mechanisms which cause telluric currents in the lithosphere

“…Radon gas is one example. The most common isotope of radon ( 222 Ra) has a half-life of 3.8 days [Jordan et al 2011]. Several thousand scientific publications have described the presence of radon as co-seismic with major events.…”

Daily earthquake forecasts during the May-June 2012 Emilia earthquake sequence (northern Italy)

“…Having said that, we also argue that the building code is not the only defense that we can have against earthquakes, and that different kinds of mitigation actions, more directed to reduce human loss that damage, can be taken over shorter time intervals [e.g. van Stiphout et al 2010, Jordan et al 2011.…”

“…Time variations of the seismic rate are more evident over the short-term (days to weeks), and in particular after a large earthquake. The modeling of these time variations and its possible use for practical purposes was discussed in depth by the International Commission on Earthquake Forecasting for the Italian Civil Protection [Jordan et al 2011], which was nominated by the Italian government after the L'Aquila 2009 earthquake. This Commission had two main tasks: (i) to report on the current state of knowledge of short-term prediction and forecasting of tectonic earthquakes; and (ii) to indicate guidelines for the use of possible forerunners of large earthquakes to drive Civil Protection actions, including the use of probabilistic seismic hazard analysis in the wake of a large earthquake.…”

“…The Commission recommended the development of operational earthquake forecasting (OEF), and of quantitative and transparent decision-making protocols that encompass mitigation actions at different impact levels, with each one associated with the surpassing of a specific probability threshold. In essence, OEF comprises procedures for gathering and disseminating authoritative information about the time dependence of seismic hazards, to help communities to prepare for potentially destructive earthquakes [Jordan et al 2011].…”