Wk 5 Summative Assessment Week 5 Exam

Disruptions to the natural world can occur from both natural disasters and human activities. These events can alter ecosystems, weather patterns, and geological processes. Understanding what qualifies as a disruption helps us prepare and mitigate risks. "Correct answer" indicates recognition of those valid disruptions, though the question is vague without specific options.

An anthropogenic hazard is caused by human activities, not natural processes. Examples include industrial accidents or pollution. In contrast, hydrological and geophysical disasters are natural events like floods and earthquakes. Therefore, anthropogenic hazards are not considered natural disasters.

Geophysical disasters are caused by geological processes, such as movements in the Earth’s crust. Earthquakes result from sudden tectonic shifts, making them classic geophysical events. While tsunamis can be triggered by earthquakes, they are classified as secondary events. Floods and droughts are categorized as hydrological and climatological disasters, respectively.

Hydrological disasters are related to the movement and distribution of water. Flooding occurs when water overflows or cannot be absorbed, making it a hydrological event. It often results from heavy rain, overflowing rivers, or dam failure. Earthquakes and landslides are geological, while droughts are climatological.

Droughts develop over time due to prolonged periods of low rainfall. They can go unnoticed until severe effects such as crop failure or water shortages appear. Unlike earthquakes or tsunamis, which happen suddenly, droughts are slow-onset disasters. Their gradual development makes early detection and mitigation critical.

When the amount of water exceeds natural or man-made storage capacities, flooding can occur. This often results from heavy rainfall or rapid snowmelt. Water bodies overflow, damaging infrastructure and ecosystems. It’s a direct consequence of water imbalance in the hydrological cycle.

Tectonic movement builds pressure along fault lines. When this pressure is suddenly released, it causes the Earth’s surface to shake, resulting in an earthquake. Earthquakes are unpredictable but often occur along active tectonic boundaries. This is a classic example of a geophysical disaster.

While factors like water and human activity contribute to landslides, gravity is the driving force that pulls loosened soil and rock downward. When the slope becomes unstable, gravity takes over. Landslides are common after heavy rainfall or earthquakes weaken support structures. Gravity ensures the downward motion once instability is triggered.

While hurricanes, typhoons, and cyclones all refer to the same type of storm in different regions, tornadoes are distinct. Tornadoes are much smaller, faster-forming wind funnels not associated with the large-scale systems of cyclones. Therefore, "tornado" is not an interchangeable term for a cyclone. Cyclones cover broader geographic and meteorological phenomena.

Tsunamis can be triggered by a variety of sudden underwater disturbances, including earthquakes, volcanic eruptions, and underwater landslides. These events displace large volumes of water, creating powerful waves. Earthquakes, especially those under the ocean floor, are the most common cause. Thus, all listed causes are valid.