Where is your current work focused?
I am looking for and describing coastlines and tsunami deposits all over the world.
Tsunamis are large and powerful ocean waves. They grow in size as they reach the shore. Most are caused by earthquakes. When this happens, big gaps may appear on the ocean floor. Water moves in to fill this gap, and a tsunami forms. Tsunamis can cause major damage as they rush inland, flooding cities.
Early in her career, Goodman studied the ancient city of Caesarea in Israel.
a beach in Ceasarea, Israel
underwater ruins in Caesarea
Describe your first dive at Caesarea
One of the excavation leaders took us out for a tour of the site. He wanted to check how our gear was working. He also wanted to see how well we could handle ourselves before the dive began.
I was the least-experienced diver in the group and very nervous. However, once we dropped into the water, we were surrounded by massive blocks of ancient building materials. At that point, I was too distracted to think about whether or not I was a good enough diver.
We cruised around ancient cement blocks covered in plants and critters. Through a space that felt like a small canyon, we could see wood that was 2,000 years old!
What were you looking for during that season of excavation?
Though some writings suggested that tsunamis happened here in the past, we didn’t have proof of tsunamis on land. One problem is that an archaeological site on a coastline tends to have a lot of sand, pottery, shell, and gravel. A tsunami deposit has the same things! This made it hard to realize that some of those layers were actually from a tsunami.
To confirm their suspicions, the team looked for evidence of tsunamis below the surface.
Goodman collects a sediment sample in a small bag.
Goodman shows students what the inside of a core sample looks like.
The first evidence was collected during underwater archaeological excavations. These are done using something called a water dredge. It’s a kind of underwater vacuum cleaner.
The evidence that we found was layers of materials that came from the deep sea mixed with materials from the shallow sea and beach. There was also material that came from the land. The mixture included pottery, shells, pebbles, microscopic organisms, patches of mud, and sometimes even largepieces of carved marble. The only thing that could cause this mix of materials would be very strong waves.
The team then linked this mix of material with what they knew about the past. They discovered that the age of the deposits matched the age of the historically described events.
The discovery was important for proving that the written records were not describing regular storms or other events, but actual tsunamis.
How large was the debris field?
We didn’t know how large the debris field might be. To find out, we needed to take core samples. For this, we need long pipes that we insert into the seafloor. This is not so easy to do in sand. You must hammer the pipe in a long time. Then you must remove it somehow.
How could we connect an automatic hammer to the top of the pipe to hammer it in? Then how could we attach ropes and floats to pull it out? It took a lot of sketching and thinking until we got it right. At first, it took 12 days to collect two core samples. Now, we can collect three cores in a day!
Goodman holds steady a pipe being used to take a core sample of the seabed.
