Science & Tech · Science & Environment · 2 hrs ago
Medieval earthquakes triggered two major tsunamis in Italy's Lake Iseo
Researchers reconstructed two medieval tsunamis at Lake Iseo in northern Italy using lake sediments, earthquake records, archaeology and a historical account.
Centuries of forest clearing and land use sent more sediment into the lake, building steep, unstable underwater banks at the Oglio River delta.
The 1117 Verona earthquake caused one bank to collapse, pushing a huge volume of water across the lake.
The researchers' models suggest waves in the lake's north may have topped 50 metres and flooded areas up to 2.7 kilometres inland in less than a minute.
A medieval manuscript describes widespread destruction in nearby villages and castles, in keeping with the researchers' reconstruction.
A second earthquake triggered another tsunami in 1222, with waves reaching about 13 metres and water travelling up to 1 kilometre inland.
The researchers warn similar disasters could happen again if earthquakes strike unstable underwater slopes.
Researchers say earthquakes triggered two major tsunamis in Italy’s Lake Iseo during the Middle Ages.
They found that centuries of deforestation, mining and grazing sent more sediment into the lake and made the river delta’s underwater slopes steeper.
The 1117 earthquake caused a landslide that generated waves estimated to exceed 50 meters in the lake’s northern area.
A second tsunami followed the 1222 Brescia earthquake, with waves reaching around 13 meters.
The researchers warn that similar conditions could make the lake vulnerable to future disasters.
- Who
- An international team of researchers studied the events. Medieval residents of nearby villages were affected.
- What
- Two earthquakes triggered underwater landslides and tsunamis in Lake Iseo.
- When
- In 1117 and 1222 CE.
- Where
- Lake Iseo in northern Italy.
- Why
- Earthquakes shook a delta made unstable by accumulated sediment, which had increased after people cleared forests for pasture and mining.
This story does not have two clearly opposing sides.
Forests around the Oglio River delta were increasingly cleared for pasture and mining, and more sediment entered the lake.
An earthquake caused the steep underwater banks of the delta to collapse, triggering a tsunami.
The Brescia earthquake triggered a second tsunami in Lake Iseo.
- Lake
- Lake Iseo, northern Italy
- First earthquake
- 1117 CE Verona earthquake
- First tsunami
- Waves exceeded 50 meters in the lake’s northern area
- Second earthquake
- 1222 CE Brescia earthquake
- Second tsunami
- Waves peaked at around 13 meters
What people are saying
Our simulations reveal that the medieval delta collapses in Lake Iseo generated some of the largest subaquatic landslide-induced tsunamis ever inferred in a lacustrine setting
The lake overflowed so much that very few of the inhabitants of the nearby villages escaped this danger. Many castles and fortresses also collapsed miserably, with the destruction of their inhabitants.