B. Explain the effects of the following:
1. Hurricanes:
2. Spreading of diseases:
3. Physical destructions:
Answers
Answer:
1. Strong winds can damage or destroy vehicles, buildings, bridges, trees, personal property and other outside objects, turning loose debris into deadly flying projectiles. In the United States, major hurricanes comprise just 21% of all land-falling tropical cyclones, but account for 83% of all damage.
Explanation:
1. Storm surge, tornadoes, heavy rainfall, high winds, riptide, and death are the most major effects of hurricanes. While a hurricane is approaching the coast, the sea level increases swiftly. Since the sea level rises, the amount of water can cause many deaths from drowning.
2. Water, sanitation, food and air quality are vital elements in the transmission of communicable diseases and in the spread of diseases prone to cause epidemics. A number of environmental factors influence the spread of communicable diseases that are prone to cause epidemics.
3. Ground shaking is a term used to describe the vibration of the ground during an earthquake. Ground shaking is caused by body waves and surface waves. As a generalization, the severity of ground shaking increases as magnitude increases and decreases as distance from the causative fault increases. Although the physics of seismic waves is complex, ground shaking can be explained in terms of body waves, compressional, or P, and shear, or S, and surface waves, Rayleigh and Love.
P waves propagate through the Earth with a speed of about 15,000 miles per hour and are the first waves to cause vibration of a building. S waves arrive next and cause a structure to vibrate from side to side. They are the most damaging waves, because buildings are more easily damaged from horizontal motion than from vertical motion. The P and S waves mainly cause high-frequency vibrations; whereas, Rayleigh waves and Love waves, which arrive last, mainly cause low-frequency vibrations. Body and surface waves cause the ground, and consequently a building, to vibrate in a complex manner. The objective of earthquake resistant design is to construct a building so that it can withstand the ground shaking caused by body and surface waves.
In land-use zoning and earthquake resistant design, knowledge of the amplitude, frequency composition, and the time duration of ground shaking is needed. These quantities can be determined from empirical (observed) data correlating them with the magnitude and the distribution of Modified Mercalli intensity of the earthquake, distance of the building from the causative fault, and the physical properties of the soil and rock underlying the building. The subjective numerical value of the Modified Mercalli Intensity Scale indicates the effects of ground shaking on man, buildings, and the surface of the Earth.