ИСТИНА

No one has no doubt now the existence of rotational components of motion during an earthquake. It is a fact that interest in this potentially new field for seismology has risen during the last years. However, often even seismologists have questions: What does rotational seismology mean, what is magic for, what hardware it has, what it can give now and what can it achieve? Are measurements of rotational ground motions useful for seismology? Here we have decided to answer these questions concisely. Both the near-field and teleseismic rotational motions must be broken down and treated separately. It is caused not only weakening of movements at distance, and, consequently, the difference of instrumentation. To understand strong ground motions we must deploy extensive seismic instrumentation along active faults. Teleseismic registration so far also open more questions and create more difficulties than it purported to solve.