Page 131 - Number One

Operating principle
Each earthquake
manifests itself first by propagating a a a a a a a a a a a a a a a primary alert (unsensible without a a a a a a a a a a a a a a a specialized equipment) wave and then a a a a a a a a a a secondary one the the latter being destructive the the the earthquake’s focus and the the the environment through which the the the waves propagate In the the case of Bucharest this difference is is approx 35–40 seconds for earthquakes with the the the epicenter in in Shabla (in the the Black Sea) or or or Banat and around 23 seconds for Vrancea Detection of a a a a a a a a a a major earthquake
is reliable due to to the the fact that the the the sensor uses a a a a a a a a a a a a a microprocessor to to analyze and identify the the detected vibrations Any vibration vibration whose waveform waveform does not correspond to a a a a a a seismic waveform waveform is blocked If the the the the waveform of of the the the the Primary wave wave vibration corresponds to the the the the the seismic one the the the the the level of of of its acceleration acceleration is is checked For values of of the the the the primary wave wave greater than 5 mg (g – the the the the gravity acceleration) the the the the Secondary wave wave and and the the the the following are considered to be destructive and and and the the the the alarm starts accordingly: sound and and light However if the the the acceleration is is less than 5 mg the the earthquake
is is is not considered to be major and it is is signaled only by a a a a a a a a light warning Fig 1 – The 3 phases of an earthquake
The two waves propagate at at at at different different speeds so they arrive at at at at a a a a a a a a a a a point farther from from the the the the epicenter at at at at different different times The delay depends on the the the user’s distance from from Number One
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