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Deep under the Ebruso region of Italy, two tectonic plates meet.

These thick slabs of hardened earth crust,

under constant strain from the slowly moving magma beneath, have buckled

into a giant ridge running down the centre of the country, the Apennine mountain range, and nestled

in one of its valleys is the city of Lakwala.

It was here on the afternoon of March 30th, 2009, that the ground suddenly moved.

There have already been months of frequent small tremors, but this is more powerful.

Life in the city continues. No real damage has been done, but anxiety levels are rising. Is that it? Or is there

worse to come? And so the next day, a group of earthquake scientists are on their way, summoned

in response to the growing disquiet. They know the long history of earthquakes in the region.

They have their models and they have studied the latest seismic data. Can they provide the

security the people of Laquilla need?

I'm Hannah Fry, a mathematician who studies patterns in human behavior.

And from BBC Radio 4, this is Uncharted, tales of data and discovery.

Just the year before, Julia Rosati had started at the university, drawn to Laquilla's small-town charm.

I was well. My studies were progressing well, and I'd settled in quite a bit.

Basically, Laquela had become my second home. The real social life in Laquela took place in the city centre,

around the Piazza Duomo, the Fontana Luminosa, and in the spring, the park in front of the basilica of Colomagium.

For Julia and her friends, earthquakes were the last thing on their minds.

I knew that Laquela, like many other cities and areas of Central Italy, was at high seismic

risk, but it wasn't something people talked about before 2009.

...