1887 was a particularly difficult year for the inhabitants of Western Liguria. Three strong earthquakes hit the area, causing casualties and the collapse of several buildings. About 20.000 were displaced and some cities were damaged so badly that they were abandoned. To find out more, we interviewed Stefano Solarino, an INGV researcher, who told us what happened in those days and the characteristics of the seismic events that struck the area.
Stefano, what happened on February 23, 1887 in Liguria?
On the morning of February 23, 1887, Western Liguria was hit by three strong earthquakes.
With its epicenter presumably at sea off Imperia, the events caused very serious damage in the towns located between Sanremo and Alassio. Many buildings collapsed, including some churches where the celebrations of the ashes were being held and the faithful gathered for the sprinkling ceremony. The concomitance with the festivity was one of the causes of the large number of human losses. In Bajardo alone, in the province of Imperia, there were 220 victims who, seized by the earthquake while participating in the religious function, crowded towards the exit, remaining buried by the collapse of the vault. Much damage was also recorded in Genoa. The "Mardi Gras" party, still in progress at the Teatro Carlo Felice, was abruptly interrupted: large chandeliers fell and people fled into the street, frightened.
How far was the shock felt?
With an estimated magnitude between 6.4 and 7.0, the main shock was felt throughout northern Italy, southern and central France, Switzerland and Tyrol.
There were 631 victims and some cities were damaged so badly that they were abandoned. This is the case of Bussana Vecchia, which was rebuilt further south in 1894.
What were the effects on the environment?
Following the first shocks, a tsunami occurred, with a retreat of the waters on the shoreline up to 10 meters in the port of Genoa but which was also significant on the coasts of Imperia, where witnesses of the event reported having found numerous fish dead from long exposure to air.
The tsunami was recorded by the tide gauge in the port of Genoa which showed, about half an hour after the seismic event, a drop in sea level of a few decimetres, caused by the retreat of the waters towards the open sea. Subsequently the sea returned to grow invading the beaches of the entire western part of the region. According to some studies, it cannot be excluded that the main cause of the tsunami was an underwater landslide.
And those on the population?
The effects on the population were tragic. About 20.000 were displaced, a large number which the local structures were unable to adequately cope with. The materials to build the shelters were scarce and aid was slow in arriving due to the constant tremors which made it difficult to organize interventions.
The situation improved only following the issue of a pro-earthquake decree by the Kingdom of Italy, promulgated in May 1887.
Among the sources that have come down to the present day, which ones have had particular importance for understanding the effects of seismic events on the environment and on the built-up area?
Of particular value are the technical reports drawn up on the disaster sites, including those drawn up on behalf of Minister Grimaldi by two important seismologists of the time, Torquato Taramelli and the priest Giuseppe Mercalli. Once they arrived at the site of the catastrophe, the two meticulously collected the available information; Mercalli immediately understood that the damage scales in use up to then were insufficient to describe the scenario that presented itself to him and decided to modify the scale of the same name, which he published at the beginning of the twentieth century, to take into account the damage observed.
The report contains valuable descriptions of the effects on the environment thanks to which we know that there were episodes of liquefaction and ground fractures, the disappearance or appearance of springs and numerous landslides.
Finally, what does this event represent for the region?
This seismic event represented an epochal turning point in the history of the region for several reasons. Up to that moment, Liguria had experienced only one destructive earthquake, in May 1831, with a limited number of losses, while the 1887 event, with an intensity at least two degrees higher than that of 60 years earlier in some localities, caused the loss of numerous human lives, in a much larger damaged area. Furthermore, following the reconstruction that lasted a long time, Liguria established the tourist vocation that still distinguishes it today. In many cases, in fact, houses capable of hosting tourists were rebuilt on the ruins and the first hotels were built. This, of course, also had repercussions on logistics and traffic.
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