Earthquake early warning videos
See a cartoon demonstrating how you can teach this in your class using a kinesthetic activity about earthquake early warning:
http://www.csun.edu/~mdalessio/files/kinestheticearthquakes.pdf
Earthquake early warning on a YouTube poster's computer, followed by shaking in their apartment.
Imagine you are watching the Japanese equivalent of CSPAN. All of a sudden, your TV pops up with an alert indicating a large earthquake is about to happen. It shows a map with the earthquake epicenter. How does the TV broadcaster know an earthquake is coming when the government officials in the video haven't felt anything. If you wait a few seconds, you can eventually see the first shaking of the P-wave hit the parliament building before they switch over to a news anchor. A few seconds after that, the anchor announces that he feels shaking. Live cameras also record the shaking around Tokyo.
The Japanese early warning system sends signals to cell phones alerting people of earthquakes. (You have to pay a small fee.
Earthquake early warning videos from YouTube for the M8.9 earthquake in Japan
You may have seen some really dramatic tsunami and shaking damage videos from Japan. These inspire awe, but also a whole lot of fear. Is fear really the message we want to send to our students? Knowledge can be a lot more empowering than fear, which is why I think earthquake early warning is a great way to teach about earthquakes. Learning about seismic waves can actually help make you safer. Some of the 10 million people in Tokyo were able to move to safety and survive with as much as 70 seconds of warning prior to the strong S-wave shaking because of a high tech early warning system. This page shows YouTube videos of that system in action.
Early warning system in action from a previous Japanese quake. This was a much smaller one. The machine alerts the family in their apartment that an earthquake is coming and counts down the seconds. The P-wave is barely perceptible. The S-wave is slightly more frightening to the child, but still no damage. Nonetheless, look at how much warning time they had.
How does early warning work?
An animation showing the early warning for Tokyo (left) and a city closer to the earthquake source (right). The city is shown as a green square at the end of the black line connected to the epicenter. The red star is the epicenter. Every circle on the map represents a seismic recording station that is monitoring vibrations in real time and sending the information back to a central computer at the speed of light. Black circle represents the faster moving P-waves spreading out from the earthquake and red circle is the much stronger S-waves. As soon as the first earthquake waves hit the first seismic recording station, the computer knows about the earthquake and can start to send out an alert. The middle number is a count down until the strongest shaking S-waves will reach Tokyo. The bottom number shows the estimated magnitude of the earthquake. Note how the magnitude estimate keeps changing as more and more seismic recording stations record the earthquake. With more data, the number is more accurate. (The top number is not very important... the magnitude revision number -- it keeps going up by one each time a new estimate of the magnitude is released).
What happens if you live in the city on the tiny peninsula closest to the red star in the right-hand video? How much warning do you get? None, because the first seismic waves to be recorded reach you at the same time they reach the first seismic recording station.
Read about the early warning system being developed in California
A very unintelligent person video taping the earthquake. Towards the end of the movie, the television flashes with a map of Japan showing the location of tsunami warnings. This warning was available about 3 minutes after the earthquake started (and before the shaking even ended for this person, who was located further from the epicenter).
Download my poster about earthquake early warning:
Read about the earthquake early warning system in Japan.
Kinesthetic Early warning
This is the presentation that I gave at NSTA on March 12 about creeping faults.
Download Slides from NSTA talk 2011