How did an ancient Roman harbor end up in ruins? Scientists realized the culprit was a long-forgotten natural disaster that left tell-tale geological clues -- and possibly an eyewitness account in an ancient religious text. But solving this mystery led to a bigger question: what if it happens again?
PETER GWIN (HOST): Once upon a time, there was a budding archaeologist and some old, old ruins. The archaeologist is named Beverly Goodman and the ruins are a city called Caesarea, on the coast of Israel.
BEVERLY GOODMAN (ARCHAEOLOGIST): So Caesarea today, when you go there, the majority of the harbor is now underwater. And then as you go off into the deeper part of the harbor, you need to go there with scuba gear in order to see it.
GWIN: Twenty years ago, Beverly was a grad student in her 20s. She was on a team diving in the Mediterranean Sea asking pretty standard questions about the harbor at Caesarea. Basically: what happened here?
GOODMAN: The harbor definitely had signs of deterioration about 100 years after it was built. But the issue was why?
GWIN: Why did the harbor sink into the sea? Some archeologists spend their whole careers asking questions like that and never find an answer.
GOODMAN: There is a picture where I'm excavating through and I'm looking at the camera with the like, oh my gosh. And of course I'm working with my supervisor and he's going, this could be it, this could be it. And, and, you know I just remember staring at this section and thinking, wow. You know? This is what we were really looking for.
GWIN: What Beverly found didn’t just change what archeologists know about this ancient city. It changed the way they think about Israel today and it may help save lives in the future.
GWIN: I’m Peter Gwin, and this is Overheard at National Geographic. A show where we eavesdrop on the wild conversations we have at Nat Geo and follow them to the edges of our big, weird, beautiful world.
This week, could a religious text hold the clues to an ancient natural disaster? And what if what happened to Caesarea, happens again? More after the break.
GWIN: So tell me about when you started digging at Caesarea.
GOODMAN: So my first experience in Caesarea was as a student. I came to get some summer credits and see some old friends and have a good time and I was –
GWIN: So you came to Caesarea to party is what you're really telling me, Beverly.
GOODMAN: Uh, Peter. My parents are gonna listen to this.
GWIN: For all those parents listening, the study abroad thing actually worked out because today Beverly is a professor at the University of Haifa in Israel and a Nat Geo explorer.
After that first trip to Caesarea in the mid-1990s, she came back as a grad student. And ever since, she’s been uncovering secrets buried along the Israeli coastline.
But how Caesarea’s harbor was destroyed? That eluded archeologists for a long time.
GOODMAN: It even kind of became a bit of a staff joke. You know, anytime we saw something that we didn't quite know what to, what to make of it we kind of go, oh yeah. That's probably the tsunami.
GWIN: Beverly is a geoarchaeologist. Her superpower is reading stories in underwater sediments. She and the team of underwater archaeologists would measure how thick different layers were and note when they found pottery or other signs of ancient people.
One day, they finished work and floated to the surface of the water.
GOODMAN: But the problem was we were sort of too early in the day to call it a day and to go and, you know, have a beer. Um, and we were too late in the day to really have the strength and energy to take all of the equipment and move on to our next target. So they said, you know what? Just keep digging. What'll it hurt, right?
GWIN: And that was the beginning of the end of the tsunami joke. Because that day, buried under the seafloor, Beverly found a strange layer of shells, pottery, and pebbles all mixed up in a jumbled mess.
GOODMAN: So this might not sound so exciting. I mean, we're working underwater and I'm telling you that we're finding shell. Okay. So, wow. Amazing, shocking, you know, revolutionary. Um, but what was really unique about it was that it was a very, very thick layer so it was nearly three feet thick.
And when you see something like that you have to go okay, well, why is it here? Um, when is this from? You know, are we looking at three feet that happened over ten thousand years? Or are we looking at three feet of a deposit that happened in a week? Um, you know, those are two very different things.
GWIN: They sent samples from the seafloor to a lab for dating. And when the results came back…
GOODMAN: Everything was giving us the same age and so that meant that it could be that this was all happening in a single short-term event.
GWIN: So this is a lightning strike? Harry Potter getting his lightning bolt scar for you.
GOODMAN: Oh yeah. Sometimes I do feel like I have this tsunami sign on my forehead.
GWIN: So if a tsunami did hit, what would it have washed away? There’s still a place called Caesarea. Today, it’s a quiet town on Israel’s coast. But around the time of Jesus, it was a sparkling city where everything was brand new.
GOODMAN: You can almost imagine this kind of, like, prefab Roman city. You know, it would have felt just, you know, had the paint not yet dried and just a very, very, very new and state of the art sort of city.
GWIN: There was an outdoor theater looking out over the sea. A brand-new arena for chariot races. And a harbor that would make Caesarea the most dominant seaport in the region.
GOODMAN: The harbor itself was a completely artificial harbor and the way that they did that is by actually putting islands out from the coastline. These artificial islands made out of wooden frames that were filled with cement. So a very, very state of the art technology at its time.
GWIN: It wasn’t just state-of-the-art. It was an audacious, aggressive building project. And all of it was driven by one man: King Herod.
HENRY ABRAMSON (PROFESSOR): On the one hand, Herod was an incredibly awful, devious, murderous tyrant. On the upside though, what an amazing visionary when it came to architecture and building.
GWIN: Henry Abramson is a professor of Jewish history and a dean at Touro College in Brooklyn. And he’s talking about one of the most notorious villains in the New Testament. King Herod is the bad guy in a story known as the Massacre of the Innocents.
ABRAMSON: Having heard a prophecy that Jesus was born, he attempted to kill all of the children born in that year.
GWIN: Jewish tradition has stories about Herod too and they don’t paint a flattering picture.
ABRAMSON: One of his wives, uh, who he was very, uh, in love with, but at the same time he felt that she was trying to betray him -- he had her murdered. But then in a fit of remorse didn't want to bury her body. So he had it preserved in a vat of honey.
GWIN: Herod and most of his subjects were Jews. But his kingdom was part of the Roman Empire and Herod wanted to show the Romans that he was one of them.
ABRAMSON: Putting up an amphitheater meant you'd have, like, gymnastics and athletics and these were things were all done by the way totally in the nude. So that was like really not something that flies very well in Jerusalem then or now. So it was like a huge statement about how it's such a great thing that Rome is now in charge of Judea and we're going to celebrate Roman culture in a very big and concrete way. Literally, right here with the architecture of Caesarea.
GWIN: Herod even named his new port city after the emperor, Caesar Augustus. And his gambit worked. Caesarea became a major Roman center in the Eastern Mediterranean. Today, the ancient city is mostly in ruins.
GOODMAN: But from the foundations it's really possible to understand what the size of the buildings were and what the styles of the buildings were. So today what they did in Caesarea is they've done a lot of reconstruction of, of the some of the larger features like the theater. So you can go and see air supply or Radiohead or the Pixies. Um, yeah.
GWIN: Wow, the Pixies and a Roman theater is –
GOODMAN: It was awesome.
GWIN: Oh you saw it?
GOODMAN: Yeah, of course I was there!
GWIN: Do people still use the harbor that's there?
GOODMAN: Well, the harbor is a whole ‘nother story.
GWIN: And that other story is not written down, even though the Romans seemed to write everything down. Beverly says there’s no written record of what happened to the harbor.
So when the lab results showed something massive happened all at once, she wondered, could it really be a tsunami?
GOODMAN: So when we first got the date back, we found that it was sometime, you know, in the early second century. And so we went straight to the published Tsunami Catalog.
GWIN: The Tsunami Catalog: definitely not where you do your holiday shopping. The Tsunami Catalog is a list compiled by geologists and historians of every single known tsunami, going back thousands of years.
GOODMAN: And there was conveniently only one event that, that actually fit with the timing of the radiocarbon dates.
GWIN: In 115 AD, there was an earthquake in Turkey. Nearly two millennia later, a historian proposed that particular earthquake caused a tsunami and so he added that date to the tsunami catalog. His evidence? One murky account in an ancient Jewish text: The Talmud.
Is this correct to say that you're a scholar of the Talmud or a Talmudic scholar?
ABRAMSON: I think either of those would be fair. Um, don't call me a rabbi, though. I'm not a rabbi, just a regular guy.
GWIN: Henry Abramson is a regular guy who has also written a couple of books about the Talmud.
So for total beginners, how do you describe what exactly is the Talmud?
ABRAMSON: So the short version of what the Talmud is is it is a massive document of over 5000 pages that is the codification of literally the conversation of thousands of people over several hundred years.
GWIN: And Henry says in all of those conversations and all of those pages, the Talmud has one, single goal.
ABRAMSON: Bringing its readers closer to God in every way possible as understood by the rabbis of the ancient world. The rabbis literally talked about like how would God want us to tie our shoes. How would God want us to eat. How does God want us to conduct business, to be married, to be divorced.
GWIN: And another thing about the Talmud: it’s not always straightforward. Henry says the traditional way to learn it is with a partner, arguing the exact meaning of each passage.
ABRAMSON: It's the kind of document where you are immersed in the argument and suddenly you'll hear a note in the symphony that you had never heard before. It’s like, oh my gosh, there's an oboe there. That changes everything without that oboe. "How did I listen to this without the oboe?"
GWIN: So what if the oboe was a description of an ancient tsunami?
ABRAMSON: You know, the first time I heard this, I knew exactly which passage she was referring to. And I said no, you can't. This can't be your -- you can't be serious.
GWIN: So I asked Henry and Beverly, what exactly is the story in the Talmud?
ABRAMSON: For cognoscenti, this is page 59b of tractate Bava Metzia. Okay, here we go.
GOODMAN: Essentially the rabbis are debating whether or not, um, a particular type of oven is kosher.
ABRAMSON: Doesn't really matter what they're arguing about but what does matter is that Rabbi Eliezer holds one opinion and all the other rabbis disagree with him.
GWIN: So the first rabbi says, if I’m right, these trees will give us a sign.
ABRAMSON: And as soon as he says this, this tree is uprooted and it flies a hundred meters away.
GWIN: The other rabbis say cool trick, but that’s not how you win an argument. But that first rabbi -- he’s not giving up. He says if I’m right and this oven is kosher, the irrigation canal will give us a sign.
ABRAMSON: And the waters in the canal began to flow backwards.
GWIN: Again, the rabbis aren’t convinced and so he ups the game and says if the oven is kosher we’ll get a sign from this very house that we’re studying in.
ABRAMSON: And the walls of the house of study began to collapse inwards.
GWIN: Yeah. The rabbis still aren’t impressed.
GOODMAN: And the rabbi council basically says…
ABRAMSON: You can’t bring a proof from a carob tree or from an irrigation canal or from the walls of a building. You can’t even bring a proof from a divine voice.
GOODMAN: God gave us the rules and our job is to interpret them.
ABRAMSON: You can’t prove your position with a supernatural occurrence.
GWIN: So, yeah, the traditional message of this story has nothing to do with tsunamis. It’s a lesson about Jewish law and how to argue. But the details: they got Beverly’s attention.
GOODMAN: If you talk about trees shifting position and walls leaning in and water running the other direction, these are actually all wonderful signs of, of earthquake activity.
GWIN: There’s one more detail. The Talmud says that after the argument, one of the rabbis was out at sea when he saw a huge wave.
ABRAMSON: It could be that the rabbis saw all of these things, all of these natural phenomena and when they codified the story, they folded that experience into the narrative. Not necessarily because they're trying to teach us seismic natural history. They want us learners of the Talmud to get closer to God.
GWIN: So now that you’ve had a little time to think about this, what do you think of her theory? As far as that this may relate to an actual, real tsunami?
ABRAMSON: Oh, I'm absolutely convinced that this passage in Bava Metzia is related to the tsunami of 115. It, it makes perfect sense. I take issue with the idea that it's “proved” by the Talmud, but it is I think a corroboration of the tsunami occurring and it certainly enriches my understanding of the Talmud. Next time I go through the whole thing I am definitely going to keep my eye out for these kind of occurrences.
GOODMAN: I really believe that a lot of these stories… While humans are very imaginative species, we have our limitations and we certainly like to describe things that have some element of truth in them.
You know, was there a flood where Noah built a boat and went on there and took two of each? Well, unlikely. Okay. Uh, but if you look at were there times in history where villages were destroyed entirely by floods? I mean, you can imagine how that would have entered into the imagination, the experience of the people.
You know, from a deep psychological level this sort of, you know, need to understand how those things happened, why they happened and, you know, incorporating them into their, into their stories. Into their religious texts.
GWIN: When you made this connection and you presented the tsunami and the Talmud, what did other archaeologists think?
GOODMAN: Yeah, it was... Okay, I'm trying to find the right sentence here.
GWIN: Let me find the nice way to say what they actually said to me.
I remember one specific lecture that I gave and I described the tsunami evidence and everything that we saw. And at the end of the talk there was absolute silence and then someone raises their hand and they call on him and he says, "Who's your supervisor?"
GWIN: Ha! Oh man.
GOODMAN: Which you know was, pretty much summed up how it was received in the scientific community in the beginning.
GWIN: So they weren’t just critical, they were belittling. But Beverly says, it was all valuable feedback.
GOODMAN: The good news is that when people are standing in front of you and giving you criticism or telling, you know, how you your work is bollocks because you know it's this, this, and that. You know, just take detailed notes. They're saving you a lot of time.
GWIN: Because where they find holes, you find answers. Beverly set out to collect more evidence. She took more extensive samples of the rock layer all along the coastline. It all pointed to a tsunami.
GOODMAN: We don't really, truly have a litmus test where we can, you know, put a piece of paper in there and it's going to come out bright orange and say, you know, yes, this is a tsunami. All that we can do is actually try to compare it to other possible ways that that these materials would end up there. And by doing that, what ended up happening was not only did we find that first event, okay? The first event that was the initial discovery but it turned out there were more events. It wasn't the only one.
GWIN: There were more tsunamis. At least six of them recorded in rock over thousands of years. Beverly reviewed notes from previous excavations and found evidence of what the tsunamis did to people.
GOODMAN: One of the things that we found in the notes were descriptions of articulated human skeletons in non-burial contexts inside thick beds of shell. So what that means is basically your tsunami Pompeii in the sense that these were probably tsunami victims that were in the debris of the tsunami itself.
GWIN: So people died from these tsunamis. Beverly was building a pretty convincing picture: several tsunamis had pummeled Israel.
And then, something catastrophic happened that made her research seem more pressing.
GOODMAN: December 26, 2004 for me was like many people in the world. Was a terrible day.
NPR NEWS TAPE: Tidal waves crashed ashore in many Asian nations. The waves were spawned by the world’s biggest earthquake in 40 years. The quake was a magnitude 9.0 and was centered off the coast of Sumatra. Thousands of people were swept away
[news continues in background]
GWIN: That tsunami killed more than 200,000 people. By far the deadliest tsunami in recorded history.
GOODMAN: There I am watching this event on the television and I just remember thinking, wow. There is tsunami risk in the Eastern Mediterranean and nobody seems to buy it.
It's a problem that I know this and not enough other people know about it. Um, and so for me I think that was a really pivotal point where I sort of understood going after this issue of the tsunami risk on the coast of the Eastern Mediterranean was something that I really needed to follow through to the end.
GWIN: It wasn’t just Beverly who gained a sense of urgency after the tsunami in 2004. It shocked countries all over the world. All of a sudden, they were reconsidering their own tsunami plans. If they even had one.
AVI SHAPIRA (GOVERNMENT COMMITTEE CHAIRMAN): I don’t know if you have been to Israel, but uh, if you go in the summer on a Saturday to the beach we have several hundreds of thousands of people on the beach. It is a major issue how to evacuate them.
GWIN: In the late 2000s, Avi Shapira took over the Israeli government committee in charge of studying the risk of earthquakes and tsunamis. Israel had had strong earthquakes in modern times, so the government knew it needed to be ready. But tsunamis?
SHAPIRA: No. No, no. We practically didn’t have any clear data about the tsunami.
GWIN: In fact, Avi says he could count the tsunami experts in Israel on one hand. So….
SHAPIRA: Beverly was just the right person to approach. And uh, yeah, we squeezed a lot of information out of her brain.
GWIN: In 2014, Beverly Goodman presented her research to a gathering of emergency response officials in Israel. After she finished, Avi Shapira took the podium and his speech was loaded with Beverly’s research. She was finally getting people’s attention.
And Israel developed its first tsunami plan.
SHAPIRA: The first problem we had is what should we prepare for? What territory could be flooded, could be inundated? And make sure that we can evacuate the people on time from these places.
GWIN: Avi retired from the committee at the end of 2015. But the current chairman picked up right where he left off. In the past few years, Israel has rolled out evacuation drills and outreach programs.
SHAPIRA: The first target was uh, schoolchildren. If you teach them, they teach their parents. We ask the Ministry of Education to train the children what to do during a tsunami warning.
GWIN: And today, on Israel’s most popular beaches, there are tsunami warning signs.
GOODMAN: I get excited all over every time I see one of these signs. When I go down to a, to a beach that I haven't been to before and I see a sign, I take a picture I think of every single one.
To know that they're there to know that um, you know it's, it's part of a larger program to try to minimize the um, sort of damage, to minimize the sort of numbers of people that will be hurt and, and lives will be lost is just a phenomenal feeling.
GWIN: Beverly still advises the committee on questions like how far inland could a tsunami reach? They’re adding more signs and working on bigger and better drills.
GOODMAN: What are the odds there'll be another tsunami? My answer is 100 percent. You know, we know from the past that tsunamis occurred. We have the historical evidence. We have the physical evidence. There will be another tsunami. We just don't know when it's going to happen.
GWIN: Beverly hopes she never sees it. But if a tsunami does sweep in just like it did in the time of the Romans, Caesarea will be prepared.
We’ll have more after the break.
GWIN: Seismologists say it’s impossible to predict exactly when an earthquake or tsunami will happen, but we know they will happen. One scientist who studies the patterns of earthquakes and tsunamis predicts another big one could hit Indonesia not too far in the future. You can read more about that in our show notes.
Also, if you want another story about the overlap between science and religion: scientists in Israel have compared stories in the Bible with sediment from the Dead Sea. One researcher made a connection between earthquakes and a Bible story of fire and brimstone. That’s also in the show notes. They’re right there in your podcast app.
Overheard at National Geographic is produced by Jacob Pinter, Brian Gutierrez, and Robin Miniter.
Our editor is Ibby Caputo.
Our Deputy Director of Podcasts is Emily Ochsenschlager.
Hansdale Hsu composed our theme music and engineers our episodes, with additional help from Jay Olszewski, Devin Ocampo, and Interface Media Group.
Special thanks to: Judah Kauffman and Max Miller and to NPR’s Morning Edition for the archival tape we used in this episode.
Overheard is a production of National Geographic Partners.
Whitney Johnson is the director of immersive experiences.
Susan Goldberg is our editorial director.
And I’m your host, Peter Gwin. Thanks for listening, and see y’all next week.