Physics of the Earth and Planetary Interiors 122 (2000) 241–249 Premonitory raise of the earthquakes’ correlation range: Lesser Antilles P. Shebalin ∗ , I. Zaliapin, V. Keilis-Borok International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Sciences, Warshavskoye sh. 79, kor. 2, Moscow 113556, Russia Received 21 February 2000; accepted 21 August 2000 Abstract We apply to the observed seismicity of Lesser Antilles a short term earthquake precursor which has been recently found by analysis of synthetic seismicity. The latter was generated by a lattice-type “Colliding Cascades” model of interacting elements. Precursor named ROC depicted premonitory increase of the earthquakes correlation range. Here, this precursor is used as a second approximation to the intermediate-term prediction. As a first approximation we use the alarms, determined in the previous publication by the algorithm Seismic Reversal (SR); it depicts premonitory reversal of territorial distribution of seismicity. We consider combined performance of both algorithms in prediction of earthquakes with magnitude 5.5 or above. Four such earthquakes occurred in the territory considered during 1984–1998. The alarms occupy 0.5% of the total time–space. Three alarms happened to be correct, two alarms were false and one earthquake was missed by prediction. The alarms are very stable to variation of adjustable parameters of prediction method. In view of this stability, such a prediction is unusually good even for retrospective analysis. We present this prediction method as a hypothesis to be tested on advance prediction. © 2000 Elsevier Science B.V. All rights reserved. Keywords: Earthquake; Prediction; Radius of correlation; Lesser Antilles 1. Introduction Studies in earthquake prediction report many evi- dences that long range correlation between the earth- quakes is reflected in some phenomena precursory to strong earthquakes. One of the examples is the remarkably successful prediction of the Haicheng earthquake in China, 1976 (Ma et al., 1990). On its first (long-term) stage this prediction was made by extrapolating migration of seismicity over the dis- tances 10 3 km. Prozorov (1975, 1994) suggested that location of a future major earthquake is marked by the ∗ Corresponding author. Tel.: +7-95-3107032. E-mail address: shebalin@mitp.ru (P. Shebalin). “distant aftershocks” — the earthquakes of medium magnitude which occur shortly after a major earth- quake but on a large distances from it, far beyond the cloud of aftershocks in usual sense. In the time scale of years many premonitory seismicity patterns are formed within areas of the linear size 10 times larger than the dimension of the source of an incipient strong earthquake (Keilis-Borok, 1990; Keilis-Borok and Shebalin, 1999); this estimation is validated by ad- vance earthquake prediction (Kossobokov et al., 1999; Vorobieva, 1990). Press and Allen (1995) have found that in the time scale tens of years this size may reach even about five times larger: earthquakes of magni- tude 6 in Parkfield, CA, are preceded by the raise of seismic activity in Grand Basins and/or Gulf of Cali- 0031-9201/00/$ – see front matter © 2000 Elsevier Science B.V. All rights reserved. PII:S0031-9201(00)00180-1