In this lesson we’ll be learning how humans can monitor natural hazards using tools such as seismic monitoring, weather satellites and warning measures. We’ll learn how this information can help mitigate the impact of these hazards.
What Are Natural Hazards?
On Sunday night, you might find yourself in the weather app on your phone, checking what’s in store for the week. When you wake up each morning, you also might check out what the weather is predicted to be for the day.
You use this information to grab a raincoat, hat, or gloves as needed.Although our daily weather isn’t usually too extreme, this is the same process that scientists use to monitor natural hazards, or elements of the physical environment that can harm people. Natural hazards have a variety of causes. Some are caused by the climate, like hurricanes and tornados.
Others are caused by movement of tectonic plates, like earthquakes and tsunamis.Natural hazards can be devastating. Earthquakes can rip apart entire highways, leave buildings in ruin, and destroy public infrastructure.
Likewise, strong hurricanes like the ones experienced in 2017 in the Caribbean can wipe out entire cities.
Just as we want to know what type of weather is coming up for the day, scientists want to monitor the likelihood of a natural hazard occurring to help mitigate the damage. The type of natural hazard will dictate how scientists monitor the risk.
Today, we’ll look at three techniques.
1. Seismic Monitoring
Earthquakes occur when tectonic plates slide past each other, called a fault line.
Tectonic plates aren’t perfectly smooth, so as they slide they get caught on each other. Pressure builds up and then suddenly, they slide past each other with tremendous force causing an earthquake. California lies on the San Andreas fault, which is why earthquakes are common in this region.
When the plates slide past each other, the energy released travels through the earth as seismic waves. Scientists have devices called seismographs that can detect seismic waves to monitor earthquakes. Seismographs are extremely sensitive and can detect earthquakes that we can’t feel ourselves. Thousands of earthquakes occur each year actually, many are just incredibly small.
Scientists can graph the number of earthquakes detected by their magnitude in a plot called a Gutenberg-Richter diagram. The diagram plots the number of earthquakes that occur each year by the magnitude. The diagram shows an important relationship which is that as you decrease in magnitude by one, there are about ten times fewer earthquakes in the given area.This information can be used to predict how many earthquakes should occur in an area per year, and thus how many more earthquakes may be occurring in the future and of what magnitude. Engineers can structure buildings appropriately, reinforce infrastructure and put evacuation procedures into place as needed to mitigate the impact of future earthquakes.
2. Weather Satellites
Weather satellites are devices that orbit the Earth, taking pictures of our atmosphere to help us predict weather patterns. However, weather satellites aren’t just for tracking the latest thunderstorm.
They can also help predict and monitor changes to the Earth’s surface like floods, fires, tsunamis, earthquakes and severe weather like hurricanes and tornados.Satellites now are able to record images nearly in real time, allowing weather forecasters to track storm movement and predict where intense storms like hurricanes will make landfall. Satellites are even equip to track wind speed, water vapor content in and near clouds, and sea level height beneath the storms. This data helps guide evacuation recommendations and other safety measures needed during a severe storm.
|3. Warning Measures
The minutes, and even seconds, before a natural hazard strikes can make the difference between life and death. Many regions that are frequented by natural hazards use early warning systems to alert citizens of the impending hazard.
The system may be through public broadcast, phone messages, or alarm systems. The intent of early warning systems is to give people enough time to evacuate the area and protect themselves.Early warning systems use GPS data about seismic activity, water vapor, and wind to give residents notice about when a natural hazard is occurring. Early warning systems aren’t predictions, they’re simply an advance notice, sometimes only minutes or seconds before a hazard happens. But, this can mean all the difference.For example, Mexico and other countries have implemented the early warning system for earthquakes, ShakeAlert, which provides texts, alarms, and public broadcasts giving resides time to get to safety. It saved many lives in the recent 8.
1 magnitude earthquake in Mexico in September of 2017. California is hoping to roll out a similar early warning system for earthquakes in 2018.
Natural hazards are elements of the physical environment that can harm people and our infrastructure, such as hurricanes, floods, fires and earthquakes. To monitor earthquakes, scientists use seismographs to detect ground shaking and can use a Gutenberg-Richter diagram to predict the magnitude and frequency of future earthquakes. Weather satellites can track storm movements to predict hurricane landfall and monitor conditions that would promote wildfires. Lastly, early warning systems can alert citizens of natural hazards as they occur giving them minutes to seconds of notice to get to safety.