18 Questions
What does Bob Dziak study in a unique way?
Plate boundaries
Which government department does Bob Dziak work for?
National Oceanic and Atmospheric Administration (NOAA)
Where did Dziak's team place the hydrophones to study the ocean floor?
Challenger Deep
What are hydrophones?
Powerful microphones for deep-sea listening
What surprised Dziak and his team about the sounds they heard at Challenger Deep?
They heard sounds from many different sources
In which landform is Challenger Deep located?
Mariana Trench
What type of sound did Dziak and his team collect using hydrophones?
Sound of plate motion in the form of earthquakes
Why do earthquakes occur at plate boundaries?
Caused by the motion of plates
Where does the Mariana Trench lie in terms of plate boundaries?
Convergent boundary
What did Dziak and his team hear more of than they had expected in the recordings from Challenger Deep?
Earthquakes
Why were Dziak and his team not surprised to hear earthquakes at plate boundaries?
Because plate boundaries tend to have a lot of earthquakes
What did the recordings from Challenger Deep teach Dziak and his team about plate motion?
Plate motion is always moving along
What landform is formed when hot mantle material cools and hardens at the edge of tectonic plates?
Mountain range
What do scientists call the landform that is created when hot mantle material cools and hardens under the ocean?
Mid-ocean ridge
Which instrument did Dziak use to study foreshocks at divergent boundaries?
Hydrophone
Where does Dziak place the hydrophone to study earthquakes at divergent boundaries?
Near mid-ocean ridges
What is one potential benefit of studying earthquakes in the middle of the ocean, according to Dziak?
Refining earthquake study tools on land
What characteristic do big earthquakes at divergent boundaries exhibit according to Dziak?
Predictable foreshock patterns
Study Notes
Listening to Earth
- Bob Dziak is a scientist who studies plate boundaries using hydrophones, powerful microphones built to travel deep underwater.
Plate Boundaries
- Dziak and his team sent hydrophones 10.99 kilometers (6.83 miles) down into the deepest part of the ocean, the Challenger Deep, an underwater canyon part of the Mariana Trench.
Challenger Deep
- The Mariana Trench lies on a convergent boundary, where two plates are moving toward each other.
- At convergent boundaries, earthquakes and volcanic activity are common.
- The trench is formed by one plate sinking under another.
Earthquakes and Plate Motion
- Dziak and his team recorded many more earthquakes than expected at the Challenger Deep.
- Earthquakes happen at plate boundaries all over the world, caused by plate motion.
- By recording earthquakes at different plate boundaries, Dziak and his team are using sound to study plate motion.
Convergent Boundaries
- Two plates are moving toward each other at convergent boundaries.
- Hot material from the mantle comes up to fill the space between them, cools and hardens, and adds new rock to the edge of each plate.
- Over time, these additions of rock form a mountain range made up of a long chain of volcanoes.
Mid-Ocean Ridges
- Mid-ocean ridges are formed when the process happens on the ocean floor.
- They can be thousands of kilometers long and are often far from land where people can easily observe them.
Divergent Boundaries
- Dziak uses hydrophones to study smaller earthquakes, called foreshocks, that occur at divergent boundaries before major earthquakes.
- Big earthquakes at divergent boundaries have a clear pattern of foreshocks, which is not seen on land.
Applications of Studying Earthquakes
- Dziak believes studying earthquakes in the middle of the ocean may help scientists refine the tools they use to study earthquakes on land.
- If earthquakes had this kind of predictability on land, it might be something scientists could use later on.
Learn about Bob Dziak, a scientist with NOAA, who studies plate boundaries by listening to them. Discover how Dziak and his team use this unique approach to gain insights about Earth's processes.
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