Has it seemed like there have been tons of natural disasters this year? 2017 has been a record breaker for natural disasters with Hurricane Irma, Hurricane Harvey, the Mexico City earthquake, floods in Southeastern US and more. These events have impacted many people by causing deaths, injuries and severe property damage. But what has caused so many disasters? These disasters are caused by many factors ranging from global warming, shifts in tectonic plates, changes in atmospheric pressure and poor city planning. Let's learn more about the natural and man made causes behind each type of disaster!
Hurricanes
While there have been hurricanes in past years, it would seem that 2017 has been a record breaker. Hurricane Irma, Harvey, and Nate have devastated the Southeastern US/Caribbean region. Hurricane Harvey has created the most havoc with a death toll of 82.
So what has been the cause of these storms? Well, hurricanes are fueled by warm water, which is why they frequently occur in locations like the Caribbean Sea. Besides the Caribbean, these storms occur other locations like the South China sea, where they are called typhoons. The earth's temperature has been increasing steadily in the past century along with ocean temperatures. The ocean has become warmer by about 1°C on average, and the sea surface temperatures that provided fuel for Hurricane Irma were 1 to 1.5°C higher than the average. Hurricanes lose their power once they reach land or cooler water, causing the winds to drop below 74 MpH.
Besides warm water, winds are an important factor to hurricanes. Wind shear, or the change in wind with height, greatly impacts hurricanes. With low wind shear, air can flow easily through the hurricane, which intensifies its damage. If there are no drying agents, hurricanes become even more powerful, because humidity strengthens hurricanes.
Also, strong winds cause up welling, in which cold water is brought to the surface. This explains why you can surf in board shorts one day, and wet suits a few days after strong winds. You'd think that these strong winds would cause an up welling effect, but significant increases in ocean temperature have pushed colder water farther below the surface. One reason that Irma was so powerful was that it moved quickly enough to prevent cooler up welled water from slowing its path. Another reason that Irma was so powerful was a lack of interaction with large land masses. This storm started near the Cape Verde islands in Africa, giving it a long runway before impacting the Caribbean and Southeastern US.
Earthquakes
Switching from a water based disaster, land based natural disasters like earthquakes can be just as devastating. Earthquakes have occurred worldwide, but Mexico and the ring of fire region are extremely susceptible earthquakes. The ring of fire region is the coastal region surrounding the pacific ocean and ranges from Chile, to Alaska, and the entire eastern Asian coast. This region is a hot spot for earthquake and volcanic activity, as 90% of earthquakes occur here. This region also has 75% of earth's active volcanoes.
Earthquakes and volcanoes are both caused by shifts in tectonic plates, or slabs of the Earth’s crust. These slabs constantly move above hot molten rock, called the mantle. When the places subduct, or one plate slides underneath another, volcanoes are created. Mexico city recently had an 7.1 magnitude earthquake, which left many dead and homeless. Mexico is a very seismological region, because it's located on the intersection of the Cocos tectonic plate and the North American Plate. These plates greatly subduct one another, creating earthquakes and large volcanoes.
Mexico also has large volcanoes such as Mt. Popocatépetl with an elevation of 17,802 ft and Pico de Orizaba at a 18,491 ft. elevation. Many volcanoes are located close to Mexico City and other factors played a significant role in earthquake devastation. For example, Mexico City was once a lake with many islands prior to the arrival of the Spaniards. Once the Spaniards conquered this area, they drained the lake, and began building modern day Mexico city. However they didn't realize that the soft lake bed sediment wasn't a strong foundation for buildings, which has magnified the earthquakes' damage.
Floods
As you can see, many natural disasters are related to each other like volcanoes and earthquakes. Floods and hurricanes are very interrelated and one example of a devastating flood was during Hurricane Harvey. Hurricane Harvey caused rain in some areas, resulting in over 51 inches during a 5 day period. These floods took its toll on the southern US, leaving more than 50 homes damaged in the Missouri City suburbs.
Flooding can be more severe than hurricanes because it's harder to adjust to buildings being underwater. Houston, located in Harris county, was a city ripe for flooding disaster due to its low sea level along with its development. This city is becoming quite popular, with 56,600 people moving to Harris County, causing more construction. The natural land can easily absorb water, but concrete can't absorb water.
So how can we prevent flooding in major metropolises? Some ways to do this include avoiding building on bayous, having irrigation ditches and detention ponds to hold water. It's best to generally build detention ponds away from major cities and Bayous are marshy wetlands. Bayous are areas where rivers run very slowly, have stagnant water and act as a natural way to contain flood water. Another way to prevent a Harvey-like disaster is to educate the public. Most newcomers aren't too familiar with Texan geography. making it important for them to realize the risk of flooding depending on where they live. A good educational tool would be to place flood gauges in local areas, which show how high water could potential rise. However, many realtors opposed to these gauges and have fought to remove them.
2017 has been a record breaking year when it comes to natural disasters. It's interesting to learn about the forces behind the disasters, to prepare ourselves in the future. These natural disasters include Hurricane Harvey, Hurricane Irma, the Mexico City earthquake and flooding in the South Eastern US, have left their toll on mankind. Global warming, shifting of tectonic plates, weak building foundations and poor city planning are responsible for these powerful disasters.
