April 27, 2011

Part of celebrating the Earth this month is recognizing its awesome power. I have written many books about natural events like tornadoes, earthquakes, tsunamis, wildfires, and many other natural occurrences that we humans classify as "disasters" for ourselves. 

A reader named Emily A. wrote last week to ask what the record is for the longest earthquake. I responded by asking her to do some research and tell us what she found out (once a teacher, always a teacher, I guess).

Emily came back with the correct answer.

Location:                    Sumatra
Date:                          December 26, 2004
Size:                          9.1-9.3
How long it lasted:      10 minutes

  This is the longest (and third strongest) earthquake that was ever recorded on a seismograph.

It was an undersea earthquake that is also known as the 2004 Indian Ocean earthquake. Like the one that happened recently in Japan, it set off a series of devastating tsunamis up to 100 feet (30 meters) high all along the coast of the Indian Ocean, killing more than 225,000 people in eleven countries. Indonesia, Sri Lanka, India, and Thailand were hardest hit. The Sumatra Earthquake happened along the Pacific "Ring of Fire," where 81% of the world’s earthquakes occur. This famous photograph is of the tsunami striking Ao Nang, Thailand.

It is difficult to measure exactly how long an earthquake lasts, because the tremors start gradually and when the big shaking stops, the actual tremor is still dying down. But, scientists think this lasted anywhere from 8½ to 10 minutes, which is very long. As a comparison, the big Northridge Earthquake that occurred in California in 1994 lasted just 15 seconds.

The Sumatra Earthquake was one of the deadliest natural disasters in history.
With a magnitude of between 9.1 and 9.3, it is the second largest earthquake ever recorded on a seismograph. 

Here is an interesting photograph, to show just how much the earth shifted during this massive quake. Some islands (like the one pictured here) grew as they were lifted above the water line, while others tipped over and partially submerged as they dropped back into the water. This island doubled in size during the quake. The land surrounding the green area was all underwater before the earthquake happened.

If you are interested in learning more about this record-breaking earthquake, Cal Tech has a website with more information, animations and graphics to explain what happened when this massive earthquake tore the earth apart across a fault break that was longer than the entire state of California.

Tsunami Photograph: David Rydevik

Island Photograph: Kerry Sieh, TO

What are you doing this Earth Month to contribute to the global effort to pledge a Billion Acts of Green? Click on "Comments," at the bottom of any Earth Day story, and tell me how you are making a difference. We will continue to accept your ideas through Thursday, April 28. Then, on Friday 4/29, we will publish all your comments in one big article, to honor each writer’s promise to protect our planet, and inspire other readers to do the same.

March 29, 2011

A 12-year-old sixth grader named Meeps, from Upper Saddle River, New Jersey, sent me this original poem after I Skyped with a class there. Hasn’t Meeps done a good job of capturing the feelings of numbness and loss that we have seen in the faces of people in photographs of the recent earthquakes in Japan and Christchurch, New Zealand? This is a very good piece of writing.

Photograph: Aftermath of 1989 earthquake in Loma Prieta, California courtesy of U.S. Geological Service/C.E. Meyer

March 21, 2011

Librarian Alissa Gonzalez wrote to me with a good question that I think many people are wondering about.

Dear Seymour: I read that many people, when receiving advanced warning of a tsunami, take their boats and sail out to sea to be safer (because the tsunami is only a huge, destructive wave at shore). I have been trying to explain this to someone with little success. Can you help me understand this better?

However, as tsunami waves get closer to shore, they pack closer together. That energy has to go somewhere, so it goes up, which means the height of the wave increases. The greater the height of the wave, the greater its destructive power, as it can wash over sea walls, over docks and boats, and even (as we saw in Japan) into communities where people live.

That’s why some sailors getting sufficient advance warning will take their ships out to sea to avoid having them crushed by the tsunami waves breaking on shore. 

Many readers have questions about earthquakes and tsunamis, and I have been writing often about them on the Seymour Science blog. You can read all about this subject by clicking on the label Earthquakes.

March 17, 2011

As the news about 9.0 earthquake and massive tsunami in Japan continues to unfold, we all feel so sorry for the people of Sendai and the surrounding area. Many people are still without adequate food, water or shelter, and it is winter there, with temperatures overnight going down below freezing. And now, survivors must worry about exposure to radiation from the damaged nuclear power plants. Nature’s power can be awesome, but also devastating, as we are seeing each day when we look at the news.

I was in a school speaking to students this week, and many of them asked good questions about the incredibly strong earthquake and tsunami that happened last week in Japan. As I was answering their questions, I found myself saying that in the long run, this is going to be a huge and valuable learning experience for scientists. I hadn’t really thought about it until that moment, but this earthquake, and in particular the tsunami, have been filmed in a way that we have never seen before. There have been many, many photographs and videos taken of the devastation following earthquakes and tsunamis over the years. But in today’s digital age with HD video cameras on many cell phones and digital cameras, we have footage the likes of which we have never seen before, particularly of the tsunami as it was actually happening.

I told the students that this is going to allow scientists to learn a lot about tsunamis, and will certainly help us improve the computer modeling and prediction instruments that drive tsunami warning systems around the world. 

Sure enough, today I found this AFP (Agence France-Presse) news story about the reaction of Australian tsunami researchers to seeing the footage. "I think the impact of the waves going across and spreading well inland on relatively flat terrain was something that we’ve never seen before," Australian tsunami expert Ray Canterford told AFP. He added that while scientists had made progress on predicting tsunamis since the devastating 2004 Indian Ocean disaster in which some 220,000 people died, there was still work to be done. "There has been progress but it’s very unfortunate for the...

March 14, 2011

So many of our readers have questions following the terrible events in Japan over the weekend. This excellent website, from the US Geological Service, separates fact from fiction, and is full of good information about earthquakes.

Parents, Teachers and Librarians: There is also a detailed Teacher Guide for my EARTHQUAKES book, which you can use with kids to use to stimulate discussion and answer questions. It is a free, downloadable resource that we provide on my website for you to use, at home or in school.

Photo: A man rides a bicycle through a debris-strewn street in Miyako, Iwate Prefecture in northeastern Japan March 12. (Kyodo/Reuters)

March 11, 2011

Japan is part of the "Ring of Fire" - the area in the Pacific Ocean that has the strongest geological activity on Earth, including many earthquakes. So, tsunamis are not new to the Japanese people. Japanese artist Katsushita Kokusai did this famous painting of a tsunami wave off the city of Kanagawa in 1829.

March 11, 2011

The terrible earthquake that hit Japan earlier today was a magnitude 8.9. That’s one of the biggest ever recorded. The devastation caused was bad enough, but the resulting tsunami is even worse.

A tsunami used to be called a tidal wave, but that’s not a correct term. Tsunamis have nothing to do with tides - those are caused by the gravitational pull of the moon (and the sun to a lesser degree). The violent shaking of the earth underneath the ocean causes tsunamis. Tsunamis can also travel across long distances on the ocean. At sea, a tsunami wave is scarcely noticeable, but when the wave comes close to shore, it builds up and up and can by many feet high. It’s too soon at this writing to know exactly what damage has been done, but it’s likely to be very great.

For readers who want to read more about earthquakes and why we seem to have had so many big ones this year, you can read my earlier blog post:  

Photograph: The tsunami crashing into homes in Natori, Japan. Courtesy Kyodo News, via Associated Press.

May 24, 2010

Today we thought we’d share some of the feedback from the In-School testing which is underway on the prototype Teacher Guide for Seymour’s EARTHQUAKES book. This testing is happening in conjunction with the creation of thirty Teacher Guides to be used with his books. They will be available online for free teacher downloads by the time schools resume in the autumn of 2010.

For those interested in the anecdotal highlights of the in-school testing, here is feedback from fellow science writer Jordan Brown, who is collaborating with us on both the writing and testing.

 Highlights of the 3rd grade class testing:

* Kids enjoyed having "Why I Wrote this Book" from Seymour Simon read aloud. One of the teachers shared her story about experiencing an earthquake in Seattle.

* As you might expect, any opportunity for children to share personal stories captured group interest. One boy told about visiting California recently and experiencing his first earthquake.

* The 3rd graders really liked the "Make a Quake" website. We did this online activity several times, changing the variables to see how damaged the building became.

* Many kids were very surprised to learn how frequent earthquakes are.

* They also enjoyed when I passed around the hard-boiled egg with the cracked shell still on (like cracked plates around Earth). Spontaneously, I had all kids press their palms together forcefully, then have one of the hands push upward, so they could imitate the motion of faults sliding passed each other.

* For the building activity, I made the challenge a bit tougher for the third graders. I told students to build a building as tall as they could—but also try to stabilize it. Otherwise, I feared they would just make long, flat structures. All but one of the buildings they made held up when, as a group, we tested them out by shaking a plastic plate beneath each model.

From the Kindergarten Testing:

* Kids loved looking at the dramatic photos when I flipped through the book—but some of the kindergartners got a little scared. I made a point of reassuring them that the chances of a big, dangerous earthquake in our area was very rare.

* Class was fascinated by the map on page 12 (in which every small red dot represents where an EQ has occurred).

* When talking about why scientists can’t predict precisely when an EQ will occur—one child made the comparison to a balloon being blown up. If you keep blowing, eventually it will pop—but you don’t know exactly when.

* Building activity was a big hit - The teacher commented that she really loved watching the groups of children having to work together to figure out a possible solution. When some of the groups had trouble coming up with a self-standing building (I only provided a small number of materials, so they had to think creatively), they got inspiration and ideas by looking at each other’s work.

If you are interested in giving us feedback on this prototype, we would LOVE to hear from you. You can download a free copy of the Teacher Guide for Seymour Simon’s EARTHQUAKES by clicking on this link.

March 2, 2010

Many kids (adults, too) are asking what is happening inside the earth,  with January’s devastating earthquake in Haiti followed so quickly by a near record-breaking quake in Chile over the weekend.

In fact, the two earthquakes happening within a few weeks of each other are a coincidence. Each quake was independent and happened along different fault lines and for a different reason. There should be no particular reason for another earthquake to happen now along a different fault line. That’s not to say that there won’t be many aftershocks along the same fault lines that the Haiti and Chile earthquake happened. There will be many of those. But there is no particular "earthquake time"  happening now. Every moment of the year, someplace on Earth the ground is shaking and we call that an earthquake.

My family sometimes jokes with me that whenever anything happens, I pipe up and say "I’ve written a book about that." At this point in my writing career, it’s nearly true!

Here are some relevant words and definitions from my EARTHQUAKES book.

FAULT:  A crack or break in the earth’s crust. A fault is caused by movement of the rock formations that make up the crust. The San Andreas fault in California stretches for one thousand miles from Mendocino to the Gulf of California. Earthquakes often occur along faults.  [Fault comes from a Latin word meaning "to fail."]

FOCUS: The origin of earthquake waves, or the location inside the earth where rocks shifted during an earthquake. From this point the energy of an earthquake speeds outward through the surrounding rocks in all directions.  [Focus is the Latin word for "hearth", the center of the ancient Roman household.]

STRESS:  The application of forces, such as tension, that tend to cause an object to change its shape or size. Stress is expressed in force per unit of area, such as pounds per square inch or grams per square centimeter.

SEISMIC: Having to do with earthquakes or other movements of the earth’s crust. Seismic waves are waves of motion in the ground produced by earthquakes.  [Seismic comes from a Greek word meaning "to shake."]

SEISMOLOGY: The scientific study of earthquakes and other movements of the earth’s crust.

With the earthquakes in Haiti and in Chile in recent weeks, some people are wondering if something special is going on inside our planet Earth. Is there a reason for all the earthquakes in the news at the same time?  Probably not. The earthquakes in Haiti and Chile are on different faults and of different kinds. Both are huge quakes and the results have been terrible. But each happened independently and they are related to each other only in the sense that they both demonstrate the enormous forces within our planet.