ИСТИНА

The Map of Expected Earthquakes (MEE) algorithm was suggested in the mid-1980s by G.A. Sobolev, T.L. Chelidze, L.B. Slavina, and A.D. Zavyalov. Over the last 30 years, the algorithm has been tested in seismically active regions all over the world, including the Caucasus, Kamchatka, the Kopet Dag, the Kyrgyz Republic, Southern California, Northeast and Southwest China, Greece, West Turkey, the Kuril Islands, and New Zealand. The average predictive effectiveness for these regions for EQs medium-term forecast with M ≥ 5.5 was JMEE = 2.56 and 3.82, with conditional probability value P(D1|K) = 70% and 90%, respectively, selected as an alarm level. This being the case, 68% and 41% of predicted earthquakes occurred in the zones with these levels of conditional probability; the area of alarm zones was 30% and 14% of the total area of observations, respectively. This is the main result of the last 30 years. However, we cannot say that the MEE algorithm is a reliable tool for a strong EQ prediction. Results of long-term testing worldwide allow to recommend developed MEE algorithm for strengthening of supervisions in the allocated zones with high (more than 70%) level of conditional probability and for acceptance necessary preventive measures on reduction of probable economic and social losses from the future strong EQs. The most recent study was the first where the MEE medium-term earthquake prediction algorithm was used to develop maps of expected earthquakes in a classical area with a transient seismic regime, namely the Koyna-Warna reservoir site (India). The local EQ catalogue for this area, covering the period of time from 1996 to 2012 (approximately 17 years) and including 4,500 earthquakes with ML = 0-6.5 magnitudes that occurred in the depth range of H = 0-20 km, was used as the database for this work. Linear dimensions of the seismic area are 40×60 km. A standard set of seismic predictors for expected earthquake mapping in seismically active regions with pronounced tectonic activity was used for the Koyna-Warna area. The results of using the MEE algorithm in the Koyna-Warna reservoir site for the first time were very encouraging. They showed that its prediction reliability was quite high and equal to JMEE = 2.76. Zones with conditional probability levels P(D1|K) ≥ 90% experienced 56.3% of all earthquakes with ML ≥ 4.0. The alarm area was 20.4 ± 8.4% of the total area of observations. The MEE algorithm was particularly efficient in predicting the strongest earthquakes in the Koyna-Warna area that occurred during the retrospective prediction period. Thus, integral predictive reliability estimates obtained when the MEE algorithm was used for the Koyna-Warna reservoir site are close to the average values of these parameters for all previous seismically active regions. These findings, firstly, may be considered proof of the flexibility of the proposed algorithm. And, secondly, this example can be useful for medium-term earthquake prediction in other seismoactive areas around high dams.