Types of earthquake damage to buildings and structures

Over the centuries and in the present decade, earthquakes has enormous capacity most of the time, many countries and cities have been struck by heavy earthquakes resulting in significant damage of structures, roads, highways  and major economic damage for these countries, and unfortunately death of thousands of people.

Earthquake Damage

How earthquakes occur ?

There are fault lines in the earth, and these faults are in perpetual motion where the regions located on these faults have obviously seismic and earthquake activity, for example: Turkey, Iran, Indonesia, India and Pakistan. So, when two tectonic plates move and slip laterally to each other causes to conserve a huge amount of pressure as an energy, when this pressure is released it causes an earthquake.

Note: to understand what are these faults, how did they form, you should read about the continental drift and tectonic plates theory

What affects the damage of earthquake ?

Ground conditions

The behavior of the structure during the earthquake and how it responses to seismic lateral load depends on the soil conditions according to the Euro Code and the ACI code where the main soil types respectively : Rock, Very stiff clay, dense sand, loose.

Bad soil ground conditions may cause damage to structures due to liquefaction, even small buildings with two and three stories could collapse if the effect of soil during the earthquake wasn't took in consideration. 
 

Building design and construction

Most of the countries that receive the greatest damage from earthquakes has such a poor structure systems, the structures hasn't been designed for the seismic load. 

However, in the case of design earthquakes resistant systems to dissipate the lateral force that caused from ground shaking from earthquakes, the Euro building code and the ACI building code which used in the USA, Asia and many countries has requirements related to the sections of the structural elements of the building (or any kind of structure: Bridge, etc ..) and for the beams, joints and for sure reinforcement requirements for these structural elements.