Saturday, April 2, 2011

Japan – Earthquakes

Earthquakes are mysterious things. We understand why earthquakes happen, but still lack the ability to predict the magnitude of a quake or when such an event might occur. Once an earthquake begins, current technology can only provide a few seconds’ warning before severe shaking arrives at a specific location. For most people, the first sign of an impending earthquake occurs only once it’s begun.

Severe earthquakes have been mentioned throughout history, with the earliest recorded quake noted in China in 1177 BC. Scientific research into earthquakes didn’t really commence until the 18th century, where one commonly accepted theory held that earthquakes were caused by subterranean air surging out of vast caves beneath the Earth’s surface. It wasn’t until the twentieth century that the notion of plate tectonics began to develop, and for scientists to begin to understand what really caused an earthquake. Earthquakes are nearly always caused by the friction and stress associated with tectonic plate movements; as plates continuously strain and push against each other, a sudden release of energy caused by one plate slipping over another can result in an earthquake.

The 21st century thus far has spawned some massive earthquakes around the globe; as of this writing, Japan alone has seen 19 earthquakes of magnitude 7.0 and above in the last ten years. The island nation is located in the infamous Ring of Fire, a volatile region that rims the Pacific Ocean for roughly 25,000 miles and is notably home to 452 volcanoes and 90% of our planet’s earthquakes. Japan lies on the edge of the junction to three tectonic plates – the Philippine, Pacific, and Eurasian Plates – which continuously shift and grind over and under one another.

Like all disasters, the Japanese earthquake and tsunami have an effect on populations far from the stricken geographic region. Millions of people around the world are moved emotionally by the tragedy, and donate to Japanese relief efforts to signify their support and human solidarity. Traces of radiation were found on planes from Japan at O’Hare Airport in Chicago, docks and vessels were destroyed on the coasts of California and Hawaii due to waves caused by the tsunami, and the destruction from the earthquake and tsunami will have economic repercussions worldwide. And according to NASA, the March 11 earthquake was powerful enough to shift the Earth’s mass so that our planet spins a bit faster, thus reducing the length of each day by 1.6 microseconds. Thus the scope of one event – an earthquake – has created a ripple effect of significant proportions throughout the world.

My picks this week focus on understanding earthquakes and their impact on local and distant communities. Throughout the week, I’ll be featuring many additional lessons and activities on our Facebook and Twitter pages, so please check those pages for lots of ideas.

Table-Top Earthquakes
Subjects: Geology, Earth science
Grade: K-12
Using an earthquake machine (materials list is included in the resource), the teacher can demonstrate how the machine’s sliding motion mimics the intermittent fault slippage that characterizes the earthquake fault zones. This demonstration of seismology for teachers and students can be used to expand lessons in earth science, physics, math, social studies, and geography. This activity was produced by the U.S. Geological Survey, a science organization that provides all types of information to scientists, policymakers, and others. Additionally, the USGS helps to help educate the public about natural resources, natural hazards, geospatial data, and other issues through lesson plans, maps, and data.

Building Structure Exercise: Designing Structures To Perform Well During an Earthquake
Subjects: Engineering, Geology, Physical science
Grade: 6-12
Did you ever notice that after an earthquake some structures have a lot of damage while others have little? There are different factors that affect how structures perform during an earthquake. In this activity, students will learn about the effect of different variables on building performance during a simulated earthquake. They’ll learn about what physical forces are at work during an earthquake, and brainstorm ways to strengthen the buildings to withstand an earthquake. This activity was produced by MCEER Information Systems, a national center dedicated to the creation and development of new technologies to equip
communities to become more disaster resilient in the face of earthquakes and other extreme events.

You Don’t Need a Seismograph to Study Earthquakes
Subjects: Geology, Physical science
Grade: 7-12
Earthquakes are difficult to predict, and most of our scientific investigation occurs after the event. This lesson will help students to understand earthquakes. Students will simulate p waves (longitudinal) & s waves (transverse) using a slinky and rope. They will simulate one of the three types of lithospheric boundaries and investigate plate tectonics at some select web sites. This lesson is aligned to national education standards, and was produced by PBS NewsHour, which covers national and international news. NewsHour also provides educational resources for both teachers and students.

~ Joann's Picks - 4/1/2011~

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