How can Europe protect itself from earthquakes when prediction remains an inexact science?
In the 1970s, scientists thought they were close to developing a reliable method for predicting earthquakes. But they proved too optimistic: it remains extremely difficult to anticipate the time, location, and magnitude of earthquakes with any precision.
In the absence of progress, resources have been channelled into forecasting based on probabilities for given locations. “Seismologists generally configure hazard in terms of some parameter of ground shaking,” explains British seismologist Roger Musson. “That’s because the effects of a moderate earthquake close to buildings could be similar to a large one further out.”
Forecasts matter not only for those who draw up preparedness plans. They are the best tools for improving building codes, insurance-rate structures and public policy. With earthquakes responsible for 35% of all economic losses from natural disasters, the right investments in infrastructure are crucial.
Three unexpected European temblors
1 November 1755
Type: Interplate Megathrust
Epicentre: Atlantic Ocean, about 200 km WSW of Cape St. Vincent
Damage: 85% of Lisbon’s buildings destroyed
Magnitude: 8.5–9.0 Mw
18 October 1356
Type: Intraplate Epicentre: Between Waldkirch and St. Peter in the Black Forest
Damage: All major churches and castles within a 30-km radius of Basel destroyed
Fatalities: At least 300
Magnitude: 6.2–6.5 Mw
gas field, NL Since 1986
Type: Man-made Epicentre: Near Slochteren
Damage: Adverse long-term outlook on structural integrity of buildings
Magnitude: Largest to date, 3.6 Mw (16 August 2013)
100 years of Italian earthquakes
Astride the African and Eurasian plates, approaching at 6 mm a year, Italy is at high risk.
Top 20 European cities at risk
*The Risk Score was created by assigning to each city a score between 0 and 1 for both population and forecast ground movement; multiplying those two produces the overall score. Since risk reflects not only the force of shaking ground, but also the proximity of people and buildings, only cities with a population above 50,000 were included.
Top 5 cities at risk worldwide
Inside a seismograph
Typical instruments comprise a triaxial broadband seismometer and 24-bit digitiser inside a stainless-steel casing. In a triaxial design, three identical motion sensors are set at the same angle to the vertical, but 120° apart on the horizontal. Vertical and horizontal motions can be computed from the outputs of the three sensors.
Infographic: Thibaud Tissot (onlab)
Ben McCluskey, LargeNetwork
Sources: Sources: EU Joint Research Centre, Global Seismic Hazard Assessment Program, Swiss Seismological Service, US Geological Survey, Güralp Systems Ltd