Soft soil can amplify the power of an earthquake by three times
Geological conditions can transform a standard tremor into a catastrophe, as soft sedimentary soils under cities like Istanbul can triple the destructive force of seismic waves compared to solid rock.
The ground beneath a city determines its fate during an earthquake. While seismic S-waves travel rapidly through bedrock, they slow down and bunch up when hitting soft alluvial soils. This transition causes the ground motion to amplify by two to three times, turning a moderate shake into a violent surge. In regions like the North Anatolian Fault, these 'site effects' are particularly dangerous because the soft sediment layers can be up to 200 meters thick.