Are earthquakes predictable?

Abstract

S U M M A R YThe answer to the above question depends on the definition of earthquake prediction. We discuss several definitions and possible classifications of earthquake prediction methods. We also consider various measures of prediction efficiency, review several recent examples of earthquake prediction, and describe the methods that can be used to verify prediction schemes. We conclude that an empirical search for earthquake precursors that forecast the size of an impending earthquake has been fruitless. Despite considerable effort in several countries, no statistically rigorous validation of proposed precursory phenomena is available; therefore, reported cases of precursors can be explained by random noise or by chance coincidence. We present evidence that earthquakes are non-linear, chaotic, scale-invariant phenomena. The most probable consequence of earthquake self-similarity is a lack of earthquake predictability as popularly defined, that is a forecast of a specific individual earthquake. Many small earthquakes occur throughout any seismic zone, demonstrating that the critical conditions for earthquake nucleation are satisfied almost everywhere. Apparently, any small shock can grow into a large event. Thus, it is likely that an earthquake has no preparatory stage. This sceptical view of current earthquake prediction efforts should not be interpreted as a statement that any further attempts to mitigate the destructive effects of earthquakes are futile. The seismic-moment conservation principle, when combined with geodetic deformation data, offers a new way to evaluate the seismic hazard, not only for tectonic plate boundaries, but also for areas of low seismicity, that is the interiors of continents. Earthquake clustering with a power-law temporal decay (Omori's law) can be used to estimate the rate of future earthquake ocurrence. Realtime seismology can facilitate relief efforts after large earthquakes and eventually provide an immediate warning of severe shaking a few seconds or tens of seconds before the shaking starts.

Identification of Complex Processes Based on Analysis of Phase Space Structures

“…The lithosphere is an extremely complex system from the point of view of both its structure and processes therein (Turcotte, 1992;Korvin, 1992;Kagan, 1994;Keilis-Borok, 1994). Dynamics of seismic processes is viewed as extremely complicated, so that the level of "turbulence" of the lithosphere exceeds that of the atmosphere (Kagan, 1994;Kagan, 1997). During more than one hundred years of instrumental observations several important characteristics of spatial, temporal and energetic distributions of earthquakes have been revealed (C.H., 1990;Turcotte, 1992;KeilisBorok, 1994;Matcharashvili and Javakhishvili, 2000;Rundle and Klein, 2000).…”

“…Nevertheless the character of dynamics of seismic processes remains the subject of intense discussions because it is directly related to the problem of earthquake prediction. Critics of earthquake prediction (Kagan, 1994;Kagan, 1997;Geller, 1999;Kanamori and Brodsky, 2001), etc. regard seismic process as completely random, while its proponents consider it as complex and high-dimensional though not random (Main, 1997;Wyss, 1997;Chelidze and Matcharashvili, 2003;Knopoff, 1999), etc.…”

Is Earthquake Seismology a Hard, Quantitative Science?

“…Manifestations of such a transport can be monitored and a warning can be issued, usually a few days or hours, in advance. Earthquakes represent a propagation of fracture with a velocity of km/s, thus if their preparation stage cannot be monitored or, as some evidence suggests (KAGAN, 1997b), is absent, the prediction can only be a statistical one.…”

“…Here we do not focus on the question of earthquake predictability in a narrow sense (KAGAN, 1997b), but rather on a broader question, why recent research in earthquake seismology has not achieved the success of other sciences. Despite an increase in the quality and quantity of data collected, there has been no major breakthrough; no significant progress has been made in understanding seismicity and earthquake occurrence.…”

“…In a recent paper (KAGAN, 1997b) temporal earthquake prediction, interpreted more traditionally, has been reviewed. Therein, I argue that, earthquake prediction as understood by the majority of geophysicists and the general public-the prediction of specific individual events-is not possible.…”