Step 1: Understanding ground motion.
Ground motion depends on properties of seismic waves, site geology, and distance from the source (epicenter).
Step 2: Check each factor.
- Wave types: Different seismic waves (P, S, surface) cause different levels of ground shaking.
- Site conditions: Local soil and rock conditions greatly amplify or reduce shaking.
- Distance from epicenter: Closer sites experience stronger motion.
- Type of structure: This affects how a structure responds to motion, but does not affect the ground motion itself.
Step 3: Conclusion.
The type of structure does not influence the ground motion itself.
Sequentially arrange the reactions of observers and type of damage during an earthquake in the increasing order of earthquake intensity measured at Modified Mercalli Intensity (MMI) Scale.
A. Earthquake is felt quite noticeably indoors, especially on upper floors of buildings. Damage: No damage. Standing motor cars may rock slightly.
B. Everyone runs outdoors. Noticed by persons driving motor cars. Damage: Considerable damage in poorly built or badly designed structures.
C. Earthquake is not felt except by a few people under especially favorable circumstances. Damage: No damage.
D. Earthquake is felt by nearly everyone, many awakened. Damage: Some dishes, windows broken, few cracks in plaster, unstable objects overturned.