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Tuesday, 17 April 2007 |
Lorna Nickson-Brown, UK
In a closing session at the conference, marine seismologist Maya Tolstoy gave an informative presentation on the sounds of the sea and how it is used for navigation, communication and exploration of the oceans. Her session focused in particular on whales and plate tectonics.
Ms. Tolstoy, a research scientist at Columbia University's Lamont-Doherty Earth Observatory, talked about underwater microphones, otherwise known as hydrophones, which are being used to listen for earthquakes and eruptions and to pinpoint their locations, which otherwise would be unrecognizable. As well as measuring the magnitude and timing of Primary (P) and Secondary (S) waves, Ms. Tolstoy talked about the importance of a third type of wave produced only by underwater earthquakes.
As she explained, "These Tertiary (T) waves travel thousands of kilometers within a layer of the upper ocean called the SOFAR channel. Hydrophones deployed in the SOFAR channel can record even small earthquakes throughout the entire ocean."
In her session, Ms. Tolstoy talked about the challenge of figuring out whether the sounds that hydrophones have picked up are due to earthquakes caused by plate movement or, in fact, volcanic eruptions. She described to the audience of educators a key pattern of showing if the source of the earthquake changes over time. "A tectonic earthquake and its aftershocks usually remain centred in one area," she said, "but earthquakes caused by an eruption often migrate due to the movement of the magma beneath the seafloor."
Ms. Tolstoy, a leading female oceanographer, has participated in much field work to support her work with hydrophones, including a cruise to the East Pacific Rise. She described the importance of oceanography in education today, emphasising the general importance of understanding how to act in an earthquake, like moving to higher ground.
Throughout the session, it was evident that her passion for her subject had been instilled in her from a young age, gaining inspiration from the popular childhood classic "Pippi Longstocking" and her own father. Ms. Tolstoy was keen to express to the educators present the importance of continuing this same interest and "fascination in the power of the planet" in their own classroom. |
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