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TECTONICS. The earthquake of Banyak Islands ☼ occurred in region of articulation of the large and small plates (see Fig.1). Tectonics here sufficiently complex, it is caused by the north-northeastern motion of Australian and Indian plates and by their sinking under the plate of Sunda, which in turn here to be crushed to the micro-plate Burma, on the north and the micro-plate Sumatra, in the south. These of micro plate compose the frontal part of Sunda Plate and are critical for the strong earthquakes in the segment of Sunda Trench, stretched from southern Sumatra to the south of Myanmar. Seismic systems Microplate Burma and Sumatra control strong earthquakes in the zone of interaction of microplates with the Australian and Indian Plates.

SPECIAL FEATURES of the earthquake Banyak Islands on the north of Sumatra dated April 6, 2010: first, it occurred in the northern tip of SS Sumatra in the border zone with SS Microplate Burma; the secondly, it had a magnitude of M=7.7, close to threshold value of 7.8 for these systems. Let us note also that this earthquake occurred after 6 months from untypical earthquake on September 30, 2009, M=7.3 (see Communication dated Oct 2, 2009). Earthquake ☼ occurred as a result of thrust faulting on the subduction interface plate boundary between the India-Australia and Sunda plates. It occurred in the slipping zone of the catastrophic Sumatra earthquake of March 28, 2005, M=8.6. However, the earthquake of 2005 had a preparation in SS Sumatra and occurred near the island Simeulue after catastrophic Nicobar earthquake 2004.12.26, M=9.1, 125 km is northern, in SS Microplate Burma (see Fig.2a). It brought into equilibrium these seismic systems in the near-boundary contact zone. Analysis in SS Sumatra showed that Banyak earthquake cannot be added neither to the strong nor to the earthquake-indicators. For its preparation seismic system Sumatra answers indirectly. It freed the accumulated static stresses in SS Sumatra for several seismic cycles as a result of the lateral contraction of the sinking Australia plate under Sumatra and evened the stressed state in the main contact zone of plates and microsplates. Untypical earthquake on September 30, 2009 with the longitudinal faulting within the Australia plate provoked Banyak earthquake, after freeing space for the slippage of Australia plate to the northeast.

SPATIAL TEMPORAL CONNECTIONS. Sumatra earthquake on March 28, 2005, M=8.6 had very important specific aftershocks activity. Aftershocks on April 10, 2005 (strongest of which had M=6.7) were localized in the zone B on 300 km southeastern from the basic zone C (see Fig.2a, b) and they had another mechanism. This allowed us to isolate them into the separate earthquake of M=6.7 with the reverse faulting inside the micro-plate Sumatra. Earthquake on March 28, 2005, M=8.6 staged earthquake on April 10, 2005, M=6.7. Thus, are a spatial-temporal connection between the slipping processes on the border of plates in the zone C with deformations within the plate of Sunda in the zone B (see Fig.2a). The process in the reverse order occurred in 2009-2010, the now already untypical earthquake of 2009 from M=7.3 in the zone B staged earthquake into 2010, M=7.7 in the zone C (see Fig.3). At the reverse process of deformation in the zone B they were localized already in the sinker Australia plate. Processes in the zones B and C, caused by accumulation and discharging of stresses in the direction SE-NW, are not controlled within the framework of SS Sumatra.

FORECASTS IN SS Sumatra, after the earthquake ☼ did not change (see Bulletin 002). Let us recall that the earthquakes on September 30, 2009 and April 6, 2010 occurred in the northern subsystem of Sumatra, where according to our forecasts the probability of earthquakes from 7.3≤М<7.8 was higher than in south; they occurred against the background growth of the probability of the earthquakes of 7.3≤М<7.8 in the northwest of Sumatra in the subsystem South of Microplate Burma. According to our forecasts in the zone A, Fig.3 occurs the preparation of catastrophic earthquake from M=8.4.