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Course: Middle school Earth and space science > Unit 5
Lesson 2: Natural hazardsNatural hazards
A natural hazard is any natural event that poses a risk to humans or the environment. Some natural hazards, such as severe weather events, can be predicted using data and technology. Other hazards, such as earthquakes, are not yet predictable. Created by Khan Academy.
Want to join the conversation?
- Is it possible for a tornado and a hurricane to be at the same spot?(11 votes)
- Yes! There are often tornadoes within hurricanes!(14 votes)
- Will a tsunami go towards a earthquake or away??(9 votes)
- what would happen if two tsunamies collide, and has this happened before?(8 votes)
- All throughout history, yes, there most likely has been two tsunamis colliding. If both waves were of equal strength, then on impact they would cancel each other out, but if one wave was bigger than the other, then the more powerful tsunami would win.(3 votes)
- What is the difference between a cyclone and a tornado.(5 votes)
- a cyclone is a very severe thunderstorm, a tornado is like a whirlpool in water but on land(5 votes)
- I live in california, and a few years ago when we used to get predicted for rain it usually never happened. Like the percentage had to be above 60% in-order for it to MAYBE drizzle. Now, we are constantly predicted rain every other week and it happens, it even rains when it says theres not gonna be any.
Why is this so? WHy has our weather changed so dramatically?(4 votes)- I live in California too so I know what your talking about.(4 votes)
- What's the difference between a Cyclone and a Hurricane?(4 votes)
- So, Hurricanes are tropical storms that happen in the Southern hemisphere and Cyclones appear in the northern hemisphere. Because of the Coriolis effect, hurricanes happen to spin clockwise, while Cyclones spin counter clockwise. Hope this helped!(3 votes)
- Who likes goats answer please it"s important!!(4 votes)
- I own goats so you can say I like them.(2 votes)
- What was the first natural hazard?(4 votes)
- Why do you sound so similar to Amy from the Big Bang theory? XD(4 votes)
- because.... SHE IS AMY(1 vote)
Video transcript
- [Instructor] Before I go to a new place, I try to do some thorough
research about it. What do I want to do there? What's the weather forecast? What's the chance that it might erupt? I learned this hard way recently. While preparing for a trip to
Mount Rainier National Park, I somehow missed that the mountain itself is actually a volcano. Though it hasn't erupted
in over a century, it has the potential to do so again, something that it would
have been nice to know more than a week before
I left for my vacation. Volcanoes are one of the
most dramatic examples of a natural hazard, a naturally occurring
phenomenon that can pose risks to humans and society. Natural hazards can be very dangerous for our communities. But scientists can help people
better understand the risks that may occur where they live so everyone can work together
to prepare safety guidelines. Different places experience
different natural hazards due to local geographic
or atmospheric conditions. For example, a storm on open
plains could spawn a tornado. Similarly, a storm over the ocean could grow into a hurricane or a cyclone by the time it reaches the coast. These coastal rainstorms, along with their colder
counterparts, blizzards, are the main natural
hazards that I may run into where I live in the mid-Atlantic. Too much rain or snow can
be dangerous, of course, but scientists have gotten pretty good at predicting weather conditions. Meteorologists use all
kinds of technologies to map where and when a storm may form. Orbiting satellites can take pictures of cloud patterns from above. Weather stations back on the surface can use electromagnetic wave fields measured through Doppler radar to determine how heavy rain is falling or how strong the wind is
blowing in those same clouds. They feed all of this and
other data into computer models that can help them predict
if the storm is severe enough to become a natural hazard. For example, this map
from the National Oceanic and Atmospheric Administration's
Weather Prediction Center shows where people can expect rainstorms, where others can expect snowstorms, and where those storms
may become powerful enough to pose risks. Despite great advances in our ability to predict natural hazards, there are some phenomena
that are less predictable, which can make them harder to prepare for. You see, the outer part
of Earth is made up of large moving pieces
called tectonic plates. These plates can grind or
slip against each other, releasing energy in the
form of seismic waves. Most of the time, we don't even notice
these tectonic movements. But especially along boundaries or fault lines in the plates, people may experience the ground-shaking tremors of earthquakes. Earthquakes can be especially dangerous in highly populated areas where they damage buildings, roads, and other forms of human infrastructure. Earthquakes are often associated
with volcanic activity, since volcanoes are often
found near boundaries and fault lines of the tectonic plates. As the plates move and magma
swells up to the surface, volcanic eruptions can release everything from clouds of gas or ash
to rivers of molten lava. An earthquake in one
location may even agitate large bodies of water enough
to generate a tsunami, a huge and powerful wave, along the coastline in another. Tsunamis can affect the local region as well as regions far away. Scientists can't predict
an intense earthquake, volcanic eruption, or
tsunami as effectively as they can a severe weather event. But they are working to better understand Earth's seismic activity
and when it poses a risk. For example, they use
tools like seismographs to determine when an
earthquake is happening and its strength or magnitude. Data from both minor and major tremors may help scientists figure out the signs that an earthquake is coming, giving communities along
fault lines an early warning to evacuate or brace themselves, rather than simply
reacting to the aftermath. Engineers can even use
the data they've recorded from past earthquakes to design buildings and other structures to
withstand the effects of future ones. Communicating what they've
learned may help places that experience seismic natural hazards to prepare far in advance, further reducing the risks that they face. Natural hazards can cause a lot of harm. But scientists are learning more every day about why they occur and how communities can remain resilient. For my trip, I studied up
on visiting a volcano zone and was relieved to find
that there's been no signs that Mount Rainier's
erupting any time soon. The whole experience really
reinforced the importance of being prepared. Even if natural hazards aren't common where you live or travel, having a preparedness plan
can help you stay safe in a scary situation. These are just some examples of how scientific
research benefits society. Now, if you'll excuse me, I'll be setting up an emergency kit for the next time I lose
power during a storm.