An earthquake An earthquake is a natural disaster associated with the sudden release of energy accumulated in the Еarth’s crust. This natural phenomenon is beyond human control and that cannot be predicted or prevented. In the seismically active regions of the planet, including Bulgaria, earthquakes are natural disasters with the highest degree of risk. This is explained by the specifics of the phenomenon – short-term, but with a strong impact with extremely inhumane consequences on a significant area.

 Where do earthquakes occur?

 They are concentrated in the seismic belts which coincide with the contact zones between the largest geostructures – the tectonic plates.

  • Main earthquake belts: Circum-Pacific Belt and the Alpine-Himalayan Belt (AH).
  • Minor: Atlantic, Indian, South African belts.
  • The main earthquake energy is released in the Circum-Pacific belt (75-80%) and in the Alpine-Himalayan belt (15-20%), all others account for app.5%.
  • The average annual total energy from earthquakes is in the range of 1-2 × 1018J and is determined by the number of the strongest earthquakes on Earth.