EARTHQUAKES and TSUNAMIS

Earthquakes and Tsunamis

in and around Malta

It is not uncommon for earth tremors to be felt in the Maltese islands. Many pass unnoticed and are only registered by the University’s seismic measuring instruments (seismographs), because they are often of a low magnitude. However, over the centuries a number of strong earthquakes did occur that caused considerable damage, although as far as we know, these never resulted in any deaths.

 

The 1693 Earthquake

Perhaps the most memorable earthquake in history is that which occurred on January 11, 1693. The quake’s epicentre was located in the eastern part of Sicily, causing total devastation in Catania, Noto, Syracuse and many other towns and villages in the region. In Malta, some of the larger churches of Valletta as well as those in Senglea and Vittoriosa also sustained structural damages to various degrees. Even the roof of the Inquisitor’s Palace in Vittoriosa collapsed, and 665 scudi were spent on its repairs (K. Gambin 2003).

Cathedral medieval Mdina in Fresco GM palacd
Mdina Cathedral destroyed in 1693

Agius de Soldanis says that in Gozo, the citadel’s collegiate church suffered some damages. De Soldanis also claims that at Sannat, the same earthquake caused part of the precipice to detach itself and collapse into the sea below. (A. Bonnici 1999). Michael Ellul mentions in his writing (1993) that the church of St. George in Rabat, Gozo was also effected. Yet, no injuries or deaths were recorded.

Meantime, in Sicily, the same earthquake caused the death of around 75,000 – some maintain that the number could have been as  many as 100,000. In Catania alone, it was estimated that around 18,000 people were killed. It is to be noted that in the port of Augusta in Sicily, where the Order of St. John operated its bakeries and wheat mills that supplied the Order’s ships with biscuits, dozens of Maltese employed there met a tragic end. Apart from these, some Maltese monks who resided in various Sicilian convents were also killed.

Mappa_Terremoto_Val_di_Noto_1693
Regions of Sicily hit by the earthquake of 1693

Why so many earthquakes in the Mediterranean

The Mediterranean region has always been and remains to this day, geologically active. Scientists believe that the continental masses that surround the Mediterranean, mainly those of Africa and Europe, are still shifting in opposing directions towards one another, causing occasionally, significant earthquakes. In addition, volcanic activities such as those of Etna and Stromboli and the magma that flows beneath the earth may also trigger such tremors. A good part of the Mediterrean region is classified as a ‘volcanic arc’, that comprise the Vesuvius in the Gulf of Naples, Stromboli, Mount Etna and several mountain ranges both on the North African coast (the Atlas Mountains), Turkey and mainland Greece and its islands.

10049_10049ESCSESAMEposterA41
Regions of the Mediterranean where earthquakes are most likely to occur

Why have the Maltese been spared death?

Although in  the main, Malta itself seems to be located (relatively speaking) at some distance away from the epicentres of major seismic activity, the islands are still susceptible to frequent tremors, sometimes local, sometimes emanating from the regions just mentioned.

OLYMPUS DIGITAL CAMERA
double stone walling of old Maltese buidlings

Perhaps one of the factors that mitigates the adverse effects of earthquakes locally, may be the way buildings are constructed and the quality of the material. These are mostly composed of solid slabs of limestone (Maltese: ġebla tal-franka). Many of the ancient buildings had their outer walls made up of a double stone surface (Malt. ħajt dobblu), with a space in between packed with small pebble-like stone and soil (Malt. mazkan). The modest height of the buildings, usually reaching two storeys high, also diminishes the risk of them being forcibly shaken and razed to the ground by tremors. Moreover, the ceilings / roofs of houses of old buildings are made of stone slabs (Malt. xorok) that rest on thick wooden beams separate from one another. The relatively short length of these stone slabs if damaged will not make the whole building collapse.

Earthquakes as registered on the Richter Scale

There are various types of measures by which to calculate the intensity of earthquakes. Three such scales are the Moment Magnitude Scale, the Mercalli Scale and the Richter Scale. Here are the basic levels as classified in the Richter Scale:

  • Scale 4.0 to 4.9:   This bracket measures the kind of earthtremors that shake small objects in the house. At the very least, the tremor is weak and sometimes not noticeable if not by instruments.
  • Scale 5.0 – 5.9: An earthquake of this magnitude can damage old buildings and others that are not solidly built close to the epicentre.
  • Scale 6.0 – 6.9: Such an earthquake may cause damages in buildings that are up to 160 kilometres away from the epicentre.
  • Scale: 7.0 – 7.9: This is a very strong earthquake that will demolish buildings in the epicentre where the earthquake originates, and may also destroy buildings that are furtherthan 160 kilometres away. This level of intensity may well correspond to the force released by the earthquake that hit Malta in 1693.

The Thera / Santorini explosion

BAL_532073_4x3
An artist’s impression of the aftermath of the explosion of Thera

If there ever was a catastrophic geological event in the Mediterranean in humankind’s existence in the Mediterranean, that would have been the tremendous eruption, or rather explosion of the volcanic island of Thera, known today as Santorini. This island is located in the Aegean Sea, some 110 km North of Crete. It is thought that this volcano which exploded some time around 1500 BC. released energy that was several times greater than an atomic bomb. So powerful was the explosion that it destroyed not only the surrounding cities, thus annihilating the Minoan culture of the Crete, but also created a tsunami, with waves that were over 13 meters high. These waves spread across the Mediterranean. We do not know at which magnitude this earthquake and the tsunami hit Malta, but one would assume that it was an invasive and destructive force. This phenomenon coincides with the last prehistoric phase of Malta, known to archaeologists as the ‘Late Bronze Age’ (1400 – 700 BC). Many archaeological sites of this period are located on high grounds, such as at Borg in-Nadur, Ġebel Ċiantar and il-Qlejgħa, close to Baħrija. Could this tremendous tsunami have been a determining factor for such communities to start inhabiting higher grounds for them to feel safe from  similar future occurrences? The eruption caused the displacement of various cultures in the Aegean and these migrated to other areas of the Mediterranean. Did this eruption cause migratory groups to reach Malta and thus destabilise the local inhabitants? Perhaps this factor might explain why Bronze Age village sites are known to have a defensive wall?

An island is born but disappears soon after

Isola-Ferdinandea-Graham-Isalnd-1831x
An artist’s eptiction of the emerging island south of Sicily

On July 17, 1831, a volcanic island emerged, some 30 kilometres south of Sciacca, Sicily. The captain of the British ship that spotted this island emerging from the sea, reported the incident to the Admiralty in Malta. The authorities did not hesitate to set sail and claim possession of the island, setting up the Union Jack before any other nation made any claims. The island continued to rise above the sea until it reached a height of 35 meters. By a month later its circumference had reached about 1000 meters. The British decided to name this rocky islet Graham Island, in honour of Sir James Graham, who was then the First Sea Lord of the British fleet. Among those who visited this island were Sir Walter Scott and his wife, who at that time happened to be in Malta. The Bourbon King of Sicily, Ferdinand, wanted this island to become part of his domain, and had this island named Fernandea. The French and Spanish governments were also interested in taking possession of it as this could prove of strategic importance to their interests. All aspirations were in vain however, because after a few weeks, the island slowly began to sink back into the depths. By December of that year, it completely disappeared below the surface. Apparently, this was not the first time that this geological phenomenon occurred.

The Messina earthquake of 1908

The Messina earthquake claimed the lives of more than 70,000 inhabitants in the city and tens of thousands more, all over Sicily and Reggio Calabria. In Sicily, at least three major oceanic waves caused significant damages and killed many people. The quake also affected Malta. This caused a tsunami to reach Malta’s shores, one hour after the earthquake occurred. The sea rose by some one metre and in Msida the water went inland to reach up to the nearby houses beyond the creek. In Marsaxlokk, the sea level also rose and crossed the main road to reach the parish church. Even in the Grand Harbour, the sea was noticed to reach a higher level than usual. Many fishing boats were wrecked, but no deaths were reported. The British immediately responded to this calamitous event and sent ships that were at the time at Malta to Messina, with medical supplies, as well as doctors, to assist the survivors.

messina terrenit
The Messina earthquake ‘s destructive  magnitude

A list of renowned earthquakes

Throughout the history of Malta, many earthquakes are recorded (sometimes as legendary events). Below is a list based on the writings of Frank Ventura and Pauline Galea (1993), to which are added a few other dates that I have come across in various sources. Whenever relevant, I have included some anecdotal information that are presented as footnotes.

blat mxaqqaq IMG_6809

List of earthquakes  

  • 16thcentury:     1528, 1537, 1542, 1562
  • 17thcentury:     1636, 1650, 1653, 1657, 1658, 1659(¹), 1693, 1694
  • 18thcentury:     1741, 1743(²), 1746 , 1761, 1789, 1793, 1799
  • 19thcentury:     1856(³), 1860, 1861, 1866(⁴), 1867, 1874, 1875, 1886(⁵), 1887
  • 20thcentury:    1903, 1904, 1907, 1908(⁶), 1910, 1911(⁷), 1914, 1917, 1923(⁸), 1937,        1972(⁹), 1983, 1990.
  • 21stcentury:     2008 (¹⁰)

(¹) 1659: The nuns of the Benedictine convent in Vittoriosa wrote to Pope Alexander VII (former inquisitor of Malta) pleading with him to assist them in finding an alternative residence for them to move into, firstly because their religious community had become bigger, numbering 75 persons, and therefore the convent was overcrowded. Apart from that, they were also concerned for their safety as they claimed that the structure of the convent was not structurally safe due to the effects of numerous earth tremors down the years (A. Bonnici 1993).

(²) 1743: Agius de Soldanis mentions this earthquake that occurred in his time (A. Bonnici 1999). He said that this happened on February 23, at 5.30 am. The quake lasted for seven and a half minutes. He states that much damage had been incurred both in Malta as well as in Gozo. In Gozo, damage was done to St. George’s Church, St. James’s Chapel, both in Rabat and Qala church.

(³) 1856 – October 12: The historian Pietru Pawl Castagna (1827 – 1907), claims that the earthquake of 1856 which occurred in his time, shocked everyone. It caused damage to the Protestant Cathedral in Valletta, and the dome of the Mdina Cathedral. The latter had had to have its fresco painting restored. The quake probably had its epicentre near Crete or Rhodes and reached a magnitude of 7.7 on the Richter scale.

(⁴) 1866: A series of earthquakes, some forty in all, were felt between mid-August and the end of September 1866.

 (⁵) 1886 – August 27: A whole series of tremors occurred at frequent intervals. These had terrified the whole population. Many buildings were damaged, including the Law Courts and some churches in Valletta, as well as the Mdina Cathedral.

(⁶) 1908: About this earthquake read the paragraph entitled ‘The Messina Earthquake of 1908’.

(⁷) 1911: The worst hit by this earthquake was Fort Chambray in Gozo probably due to the clay layer that lies beneath the forth.

(⁸) 1923, September 18: This earthquake is mentioned by Mikiel Spiteri (better known as Kilin) in his memoirs Fuq il-Għajn tal-Ħasselin. He says that this earthquake had damaged the chapel at Tal-Virtù, in Rabat.

(⁹) 1972, March 21, 11.06 pm: This was one of the strong earthquakes that I recall during my lifetime. This struck  during the night. Many were terrified by the quake’s magnitude and many families abandoned their homes in the middle of the night in search of open spaces away from buildings. Many were reluctant to return home, until a few days later.

(¹⁰) 2008, January 7, 12.35 pm: Another earthquake that occurred during my lifetime. This time I was at my workplace, in the ancient building of the Auberge d’Italie, in Merchants Street, Valletta. The centuries old but massive building shook violently for about five seconds. I did what I was taught to do in such a situation and sought shelter under the lintel of a doorway that led to another office. The building held its own, thus allowing me and the rest of Malta to recall the incident.

Martin Morana

18 May 2022.

Bibliography

Abela Mary Pace, ‘Earthquakes in Malta: Storms and Tremors in 1343’, 
Heritage Encyclopedia, Vol V. Midsea Books Ltd.
Barbano Maria Serafina & Rigano Rosaria, ‘Earthquake sources and seismic 
hazard in Southeastern Sicily’. Annali di Geofisica, Vol 44, August 4, 2001.
Bonnici Alexander, Gozo Ancient and Modern Religious and Profane - Canon 
Giovanni Peietro Francesco Agius - DE SOLDANIS 1712 - 1770. Media Centre 
Publications. 1999.
Bonnici Alexander, Maltese Society under the Hospitallersin the Light of the
 Inquisition Documents’, Hospitaller Malta 1530 - 1578. Ed. V. Mallia 
Milanes. 1993.
Camilleri Joseph C., ‘Graham Island in the Mediterranean’, Malta Year Book, 
pp. 530, 531.  
Ellul Michael, ‘The Earthquake of 1693’, Mdina and the Earhquake of 1693. 
Ed. Can. John Azzopardi. Heritage Books (Print Services Ltd), 1993.
Galea Pauline,   ‘Seismic history of the Maltese islands and considerations on seismic risk: Earthquakes in Malta'Annals of Geophysics50 (6): 725–740. Retrieved 5 June 2015.
Gambin Kenneth, The Inquisitor’s Palace, Heritage Books. 2003.
Grima Joseph F., ‘The Earthquake of 1693’, Kultura, Vol. 1 issue no. 3.
Inguanez John, Ġrajjiet Malta fl-Imgħoddi, PIN. 2000.
Kilin (Spiteri Mikiel), Fuq il-Għajn ta’ San Bastjan. Pubblikazzjoni Bugelli
 Publications. 1993.
Ventura Frank & Galea Pauline, ‘The 1693 Earthquake in the context of Seismic Activity, in the Central Mediterranean Region’, Mdina and the Earthquake of 1693. Ed. Can. John Azzopardi. Heritage Books (Print Services Ltd), 1993.
‘Recent and past earthquakes in Malta. Interactive map. Volcano Discovery 
(website).
https://www.volcanodiscovery.com/earthquakes/malta/largest.html
‘Are Maltese Buildings Earthquake Ready?’ Times of Malta, January 10, 2022. 
https://timesofmalta.com/articles/view/are-maltese-buildings-earthquake-
ready.925630?utm_source=tom&utm_campaign=newsletter&utm_medium=email&utm_
content=2022-01-11
https://vassallohistory.wordpress.com/earthquakes-in-malta/
‘What is the Richter Scale magnitude’, GNS Science (website).
https://www.gns.cri.nz/Home/Learning/Science-Topics/Earthquakes/Monitoring-
Earthquakes/Other-earthquake-questions/What-is-the-Richter-Magnitude-Scale

 

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