At 6:58 am on December 26, 2004, one of the most powerful earthquakes ever recorded began shaking the Pacific seafloor about 150 miles off the west coast of the Indonesian island of Sumatra. Within moments, the magnitude 9.0 quake gave birth to a tsunami — a wall of fast-moving water that is one of the most feared of all natural disasters.

The word tsunami comes from two Japanese words: tsu, which means harbor, and nami, which means wave. In English, tsunamis are often called tidal waves, but they have nothing to do with the tide. As NATURE’s Violent Hawaii shows, tsumanis are formed when an earthquake, landslide, or even the impact of a meteorite displaces huge amounts of water, sending it rolling at speeds of more than 500 miles per hour across the open ocean. As the tsunami travels into shallower water, near coasts, it slows down and the sloping seafloor pushes the waves upward — resulting in waves that can be several hundred feet high. The powerful flood waters can wash far inland, sweeping everything in their path back out to sea.

The effects can be devastating, as the Indian Ocean tsunami showed. Within hours of the initial earthquake, shorelines thousands of miles away were pummeled by waves as high as 30 feet. Fishermen, tourists, and coastal residents in Indonesia, Sri Lanka, India, Thailand, the Maldives, and even as far away as Somalia had little inkling of what was coming due to the speed of the wave and, more importantly, the lack of a tsunami warning system in the Indian Ocean. At last count, more than 155,000 people have been killed and more than 1.7 million displaced in what is being called one of the worst natural disasters of the last 100 years.

Hawaii was hit by a devastating tsunami in 1946 (shown above) and in 1960.

The Indian Ocean tsunami has also served to remind us of past tsunamis. In Alaska and Hawaii, people recalled the 9.2 trembler that hit Alaska’s Prince William Sound in 1964, sending a powerful tsunami barreling across the North Pacific. More than 100 people were killed in Alaska, California, and Oregon.

In 1960, a giant quake struck near Chile, hurling tsunami swells of up to 75 feet high against the country’s coastline. The floodwaters penetrated more than a quarter-of-a-mile inland and at least 200 people died. But the worst wasn’t over. The tsunami raced outward from the quake site, crossing the Pacific at jetliner speeds. Six thousand miles away in Hawaii, officials began to broadcast warnings that the tsunami was due around midnight. It struck hardest at Hilo, where a 35-foot wall of water snuffed out a power plant and swept away more than 60 people. Overall, up to 3,000 people died along the Pacific Rim that day.

Prior to the Indian Ocean tsunami, the most recent devastating tsunami struck Papua New Guinea on July 17, 1998. Sparked by a magnitude 7.1 earthquake that struck off the coast, it sent 30-foot waves crashing into seaside villages, killing more than 2,000 people. Papua New Guinea, like Indonesia, is within the “Ring of Fire,” an area in the Pacific Ocean where earthquakes are almost a daily occurrence.

Today, partly as a result of these historic disasters, some nations have established a tsunami warning system monitoring the Pacific Ocean. It is activated within moments of a potentially dangerous earthquake or landslide. Several countries affected by the 2004 tsunami are now working on a system for the Indian Ocean. Although the Pacific Ocean warning system has saved many lives, tsunamis remain difficult to predict, in part because the seafloor’s topography can steer them in surprising ways. Tsunamis are one of nature’s least predictable and most dangerous events.

Background:
An earthquake is caused by a sudden rupture or movement in the earth’s crust, usually due to the release of tectonic stresses which have accumulated over time. Seismic waves radiate from an earthquake’s epicenter as energy from the rupture is transferred and dissipated through the earth. When this rupture occurs underwater, water is also displaced, creating massively destructive waves called tsunamis. These clips from the NATURE episode “Can Animals Predict Disaster?” examine the tsunami of December 26, 2004. They challenge students to theorize about how animals’ greater sensitivity to seismic waves might have given them a lifesaving warning about the disaster which claimed over a quarter million human lives.

Suggested Focus Questions:

Clip 1: Destructive Forces

1. What are some possible historical instances of animals fleeing an upcoming natural disaster?
2. What might be some explanations for these flights?

Clip 2: Waves of Destruction

1. What causes a tsunami?
2. Why would the seismic waves traveling though the earth move so much faster than the tsunami’s waves of water?

Downloadable QuickTime versions of the video segments:
(Note: To downoad a video, right-click on the video title and click “Save Link As…” or “Save Target As…” On a Mac, press the CTRL key and simultaneously click the mouse, then save the link.)

Clip 1: “Destructive Forces”
Clip 2: “Waves of Destruction”

GRADE LEVEL: 9-11

TIME ALLOTMENT: Three or four 45-minute class periods

OVERVIEW:

The rupture that occurs when bending stresses within earth’s rock exceeds the strength of the rock itself is known as an earthquake. Earthquakes cause seismic waves, which move both through earth and along its surface. Earthquakes can occur anywhere near earth’s surface, but most often happen at the boundaries between lithospheric plates. The seismic waves generated by earthquakes represent a transfer of energy, and can be recorded by devices known as seismometers. The seismic waves earthquakes generate are also used to investigate the structure of earth’s interior.

Earthquakes are significant natural hazards capable of destroying life and property on a massive scale. Scientists are anxious to perfect the art of predicting earthquakes to save lives and limit economic loss, but have achieved very limited success. The additional danger posed to coastal development by earthquake-generated tsunamis lends urgency to this task.

In this lesson, students will identify methods for detecting and locating earthquakes, utilizing excerpts from the NATURE episode “Can Animals Predict Disaster?” The class will simulate the action of P and S waves, and analyze seismic data and use seismic data to determine the epicenter of an earthquake.

Student understanding will be assessed throughout the lesson using a self-check quiz, a knowledge tracking chart, responses to in-class discussions, and successful completion of virtual lab activities. Students should have basic knowledge of waves, wave propagation, and potential energy prior to completing this lesson.

This lesson can be used immediately before students complete the New York State Regents Earth Science Lab activity “Locating an Epicenter.” It can also be used prior to the NATURE: Window into Science lesson “Feeling Hot, Hot, Hot!”

SUBJECT MATTER: Earth Science

LEARNING OBJECTIVES:

• Express an understanding of the dynamics of earthquakes;
• Explain the basic principles of plate tectonics, as they relate to earthquakes;
• Explain how the energy released in an earthquake travels as P waves, S waves, and surface waves;
• Describe how earthquakes can be detected and located;
• Compare the differing behaviors of P waves and S waves;
• Recognize P waves and S waves on a seismograph;
• Utilize data and graph skills to determine the epicenter of an earthquake.

STANDARDS AND CURRICULUM ALIGNMENT:

National Science Education Standards:

CONTENT STANDARD D: Earth and Space Science

All students should develop an understanding of:

Energy in the Earth System

• Earth systems have internal and external sources of energy, both of which create heat. The sun is the major external source of energy. Two primary sources of internal energy are the decay of radioactive isotopes and the gravitational energy from the earth’s original formation.
• The outward transfer of earth’s internal heat drives convection circulation in the mantle that propels the plates comprising earth’s surface across the face of the globe.
• Heating of earth’s surface and atmosphere by the sun drives convection within the atmosphere and oceans, producing winds and ocean currents.

New York State Regents Core Curriculum Alignments

Physical Setting: Earth Science Core Curriculum

STANDARD 1: Analysis, Inquiry, and Design: Scientific Inquiry:

Key Idea 1: The central purpose of scientific inquiry is to develop explanations of natural phenomena in a continuing creative process.

STANDARD 2: Students will access, generate, process, and transfer information, using appropriate technologies.

Key Idea 1: Information technology is used to retrieve, process, and communicate information as a tool to enhance learning.

STANDARD 4: Students will understand and apply scientific concepts, principles and theories pertaining to the physical setting and living environment and recognize the historical development of ideas in science.

Key Idea 2: Many of the phenomena that we observe on Earth involve interactions among components of air, water, and land. Earth may be considered a huge machine driven by two engines, one internal and one external. These heat engines convert heat energy into mechanical energy.

PERFORMANCE INDICATOR 2.1

Use the concept of density and heat energy to explain observations of weather patterns, seasonal changes, and the movement of Earth’s plates.

2.1l. The lithosphere consists of separate plates that ride on the more fluid asthenosphere and move slowly in relationship to one another creating convergent, divergent and transform plate boundaries. These motions indicate that Earth is a dynamic geologic system. These plate boundaries are the sites of most earthquakes, volcanoes and young mountain ranges.

2.1k The outward transfer of Earth’s internal heat drives convective circulation in the mantle that moves the lithosphere plates comprising Earth’s surface.

2.1j Properties of Earth’s internal structure (crust, mantle, inner core, and outer core) can be inferred from the analysis of the behavior of seismic waves (including velocity and refraction).

Analysis of seismic waves allows the determination of the location of earthquake epicenters, and the measurement of earthquake magnitude, this analysis leads to the inference that Earth’s interior is composed of layers that differ in composition and states of matter.

STANDARD 7: Students will apply the knowledge and thinking skills of mathematics, science, and technology to address real life problems and make informed decisions.

MEDIA COMPONENTS:

Video

NATURE: Can Animals Predict Disaster?, selected segments:

Clip 1: “Destructive Forces”

Describes instances of animals mysteriously surviving natural disasters.

Clip 2: “Waves of Destruction”

Anatomy of a tsunami.

Access the streaming and downloadable video segments for this lesson on the Video Segments Page.

Web sites:

Dynamic Earth

This interactive site allows users to delve into the earth’s interior, learn about its tectonic plates and their movements, and discover how mountains, volcanoes, and earthquakes are formed.

Seismograph

This site features an image of a seismograph.

Virtual Earthquake

This activity illustrates how seismic waves are used to locate an earthquake’s epicenter.

Materials

For the class:

• One computer with Internet access for class demonstration
• One LCD projector for the computer
• A hard-boiled egg with a cracked shell
• Water
• Pen
• Plastic ruler
• Stick or twig
• Glob of play-dough or clay
• Rubber band
• Safety goggles (for teacher)
• A slinky
• Stressed Out! Self Check Quiz Answer Key (PDF) (RTF)
• Stressed Out! Vocabulary Organizer Answer Key (PDF) (RTF)

For each group of 3-4 students:

• Computer with Internet access
• A tuning fork
• A 1000ml beaker

For each student:

• Knowledge Tracking chart (PDF) (RTF)
• Stressed Out! Self Check quiz (PDF) (RTF)
• Stressed Out! Vocabulary Organizer (PDF) (RTF)

PREP FOR TEACHERS:

Prior to teaching this lesson, you will need to:

Preview all of the video clips and Web sites used in the lesson.

Download the video clips used in the lesson to your classroom computer, or prepare to watch them using your classroom’s Internet connection.

Bookmark the Web sites used in the lesson on each computer in your classroom. Using a social bookmarking tool such as del.icio.us or diigo (or an online bookmarking utility such as portaportal) will allow you to organize all the links in a central location.

Gather the necessary materials listed above in advance of teaching the lesson. Download and print each of the student organizers listed above, and make copies for each student in your classroom.

Read through the lesson prior to class, and try out each of the activities. When practicing the tuning fork activity, try varying the depth at which the tuning fork is placed in the water to get the best waves; you may get best results by keeping the fork closer to the surface of the water.

Next: proceed to Activities

In interviews with scientists and eyewitnesses, NATURE probes the evidence that some animals may have senses that allow them to predict impending natural disasters long before we can. This film premiered on November 13, 2005.

Animals and Earthquakes
http://animalsandearthquakes.com
Learn more about scientific studies on animal behavior preceding earthquakes. Read interviews with James Berkland and Motoji Ikeya, both featured in the film.

Infrasound
http://en.wikipedia.org/wiki/Infrasound
Get the lowdown on low sounds from Wikipedia.

Fauna Communications
http://www.animalvoice.com/
Learn more about Liz von Muggenthaler’s studies on animal commmunication.

Elephant Rumbles
http://www.pbs.org/saf/1308/segments/1308-2.htm
Caitlin O’Connell-Rodwell, featured in the film, tests an elephant’s ability to “hear” with her feet.

Four Ears to the Ground
http://www.findarticles.com/p/articles/mi_m1134/is_3_111/ai_84545901
Explore elephants’ abilities to “hear” and communicate with infrasound.

Hippos and Infrasound
http://acp.eugraph.com/elephetc/hippo.html
Learn how hippos communicate above and below water via infrasound.

Indonesian Tsunami Infrasound
http://www.aip.org/149th/garces.html
Listen to the infrasound generated by 2004’s Indian Ocean earthquake and tsunami.

Can Animals Sense Earthquakes?
http://news.nationalgeographic.com/news/2003/11/1111_031111_earthquakeanimals.html
The belief that animals can predict earthquakes has been around for centuries.

Shark’s Sixth Sense
http://www.findarticles.com/p/articles/mi_m0BQK/is_3_10/ai_n13778822
Find out more about shark behavior prior to Hurricane Charley in August 2004.

Books:

Hickman, Pamela. ANIMAL SENSES: HOW ANIMALS SEE, HEAR, TASTE, SMELL AND FEEL. Minneapolis: Kids Can Press, 1999.

Hough, Susan Elizabeth. EARTHSHAKING SCIENCE: WHAT WE KNOW (AND DON’T KNOW) ABOUT EARTHQUAKES. Princeton: Princeton University Press, 2004.

Ikeya, Motoji. EARTHQUAKES AND ANIMALS: FROM FOLK LEGENDS TO SCIENCE. Osaka: Osaka University, 2004.

Kaner, Etta. ANIMAL TALK: HOW ANIMALS COMMUNICATE THROUGH SIGHT, SOUND AND SMELL. Minneapolis: Kids Can Press, 2002.

O’Connell, Caitlin. THE ELEPHANT’S SECRET SENSE: THE HIDDEN LIFE OF THE WILD HERDS OF AFRICA. New York: Simon & Schuster, 2007.

Tibballs, Geoff. TSUNAMI: THE MOST TERRIFYING DISASTER. New York: Carlton Books, 2005.

Turner, Matt. ASIAN ELEPHANTS (ANIMALS UNDER THREAT). New York: Heinemann Library, 2005.

We’ve all heard them: the tales of dogs barking before the big earthquake hit; wildlife behaving strangely before the big hurricane; earthworms pouring out of the ground just before the big flood strikes.

Tall tales … or true?

Researchers say it’s probably a little bit of both. Plenty of studies have shown that some animals can sense major changes in the weather. Worms, for instance, are known to flee rising groundwater. Birds are known to be sensitive to air pressure changes, and often hunker down before a big storm. And in Florida, researchers studying tagged sharks say they flee to deeper water just before a big hurricane arrives. They also may be sensing the air and water pressure changes caused by the big storm.

Geologist Jim Berkland claims to have a formula that uses animal behavior to accurately forecast earthquakes.

“I think these animals are more attuned to their environment than we give them credit for,” Michelle Heupel, a scientist at the Mote Marine Laboratory who worked on the shark study, has told reporters. “When things change, they may not understand why it’s happening, but the change itself may trigger some instinct to move to an area that is safer for them.”

But can your kitty or puppy give you a cue that a big quake is coming? Researchers are skeptical. After years of study, the U.S. Geological Survey has this to say: “Changes in animal behavior cannot be used to predict earthquakes. Even though there have been documented cases of unusual animal behavior prior to earthquakes, a reproducible connection between a specific behavior and the occurrence of an earthquake has not been made. Animals change their behavior for many reasons and given that an earthquake can shake millions of people, it is likely that a few of their pets will, by chance, be acting strangely before an earthquake.”

What about other animal trends? In NATURE’s Can Animals Predict Disaster?, for instance, one geologist says he sees an increasing number of missing pets documented in the local classified ads just before an earthquake strikes in California. He, in fact, predicted the famous San Francisco earthquake of 1989. The theory is that the animals are fleeing the impending quake.

Again, other scientists doubt this. USGS scientists, for instance, say even simple science fair projects will show little statistical association. (See Do Lost Pet Ads Predict Earthquakes?)

Similarly, scientists are skeptical that any special “sixth sense” helped animals survive the great tsunami that swept the Indian Ocean in 2004. After the wave, people reported seeing animals fleeing to forests on high ground and finding few bodies of dead animals. But scientists note that little hard data exists, and that many animals may have survived simply because they are strong swimmers or able to scamper up trees.

Still, researchers like Liz Von Muggenthaler — who appears in NATURE’s Can Animals Predict Disaster? — believe animals can pick up the “infrasonic” sound pulses created by storms and earthquakes, and get a head start on fleeing to safety. It would make sense, she says, that the animals learn to associate such signals with danger.

But we should be careful not to give animals super-powers, says Whit Gibbons, an ecologist at the University of Georgia. “I always like stories of animals outsmarting humans, [but] I really don’t think animals have any special powers beyond those that help them in their daily lives,” writes Gibbons. “I do not doubt that many animals detect certain natural signals, such as the early tremblings of an earthquake, long before humans. This means they have opportunity to react before we can. But to think they are reacting any differently from someone who runs for an exit at a shout of ‘fire’ is to give wildlife more credit than is deserved.”

“As far as running inland to get away from a tsunami, I think an antelope, flamingo, or any other fast animal would probably do so because that’s where the forests are. Feeling a trembling earth, even if minutes before we would feel it, would not give much guidance to a running or flying animal other than a response to seek safety. The woods are the safest place for most animals, so when they flee from a shoreline they go inland, which means not only woods but higher ground. Completely natural and not at all mystical.”

Bill Barklow, a researcher who appears in this week’s NATURE, also believes animals aren’t specially adapted to avoid disaster. “I think it’s really unlikely that hippos or any animal has evolved behavior to avoid tsunamis specifically,” he says. “When they hear these infrasonic sounds that are produced by earthquakes, which happen very infrequently, they probably are just terrified of that very deep, heavy sound coming from a wide angle distant area and they just want to get out of there. So there’s a secondary benefit here. They haven’t evolved an escape behavior for tsunamis, but they are responding to infrasound, which has evolved for communication purposes.”

Did the elephant know the deadly wave was coming?

That’s the question explored by NATURE’s Can Animals Predict Disaster?

In interviews with scientists and eyewitnesses, NATURE probes the evidence that some animals may have senses that allow them to predict impending natural disasters long before we can.

Some creatures, for instance, may be able to “hear” infrasound, — sounds produced by natural phenomena, including earthquakes, volcanoes, and storms, that are inaudible to the human ear. This ability may give elephants and other animals enough time to react and flee to safety.

Another explanation may lie in animals’ sensitivities to electromagnetic field variations. Quantum geophysicist Motoji Ikeya has found that certain animals react to changes in electrical currents. He now regularly monitors a catfish, the most sensitive of the creatures he has tested, to aid him in warning others of coming disaster.

Follow NATURE as it reexamines ancient ideas about how animals can predict disaster which are now gaining credence in scientific circles.

To order a copy of Can Animals Predict Disaster?, visit the NATURE Shop.

Online content for Can Animals Predict Disaster? was originally posted November 2005.