1962 Irpinia earthquake

Last updated

1962 Irpinia earthquake
Italy relief location map.jpg
Bullseye1.png
UTC  time1962-08-21 18:19:33
ISC  event 875196
USGS-ANSS ComCat
Local date21 August 1962 (1962-08-21)
Local time18:19 CET [1]
Magnitude6.15 Mw  [2]
Depth9.0 km (5.6 mi) [3]
Epicenter 41°13′N15°01′E / 41.22°N 15.01°E / 41.22; 15.01 [3]
Type Strike-slip
Areas affected Italy
Max. intensity MMI IX (Violent)
Casualties≤20 dead

The second shock in the 1962 Irpinia earthquake (terremoto dell'Irpinia del 1962) sequence was the largest and most destructive in a series of earthquakes in the southern Apennines. It occurred on 21 August at 18:19 CET, [1] measuring Mw 6.15 and assigned a maximum intensity of IX (Violent). [2] It was preceded by an Mw  5.68 foreshock, and followed by a 5.34 aftershock. The earthquakes resulted in nearly 20 fatalities and significant property losses.

Contents

Tectonic setting

The central Italian Peninsula is dominated by active extensional tectonics, forming the Apennine Mountains. One explanation is that slab rollback is occurring within the Adriatic plate as it subducts beneath the Tyrrhenian Sea. Another explanation is because the back-arc basin in the Tyrrhenian Sea opening at a faster rate than the African plate is colliding with the Eurasian plate. [4] Extensional tectonics in the region have been active since the Pliocene epoch, mainly accommodated by northwest–southeast striking normal faults. [5] The faults associated with large earthquakes on the peninsula are geologically young in age, and rarely rupture the surface. Occasionally, strike-slip events like the 1456 Central Italy earthquakes, as well as the 1971 (Mw  5.0) and 2012 (Mw  4.6) moderate earthquakes in the southern Apennine region suggest the dominant style of faulting is not limited to normal dip-slip. [3] Strike-slip faults on the Italian Peninsula are oriented east–west.

Geology

Prior to the occurrence of the large foreshock at 18:09, a series of foreshocks were already present in the afternoon that same day. The mainshock struck at 18:19 with a moment magnitude of 6.15 Mw  and Richter scale magnitude of 6.1 ML . Very few aftershocks were instrumentally recorded; the largest measured 5.4 ML . Both the foreshock and mainshock occurred at a depth of 8 km, based on waveform analysis, [1] but this result is still controversial and unreliable. The lack of documented surface ruptures further instigated controversy into the mechanism of the earthquakes. The seismology community debated between strike-slip and normal faulting as the cause. [6]

A study in 2016 reevaluated its depth to 9 km, and generated a reliable strike-slip focal mechanism. [6] The epicenters are located between the zone of northwest–southeast trending normal faults and east–west striking strike-slip faults. The earthquake sequence represent strike-slip faulting with small normal components along either east–west or north–south trending faults. The location of the 1962 earthquakes is close to the faults that triggered the 1456 earthquakes. [3]

Impact

The first of three severe shocks occurred at 18:09 local time. While it did not cause any damage, it was felt strong enough to frighten residents in Benevento and Avellino. Many residents were driven out of their homes in fear of further shocks. The second shock was the most destructive and violent. It damaged 68 municipalities across the provinces of Benevento and Avellino. A maximum intensity of IX was assigned in the towns of Melito Irpino, Molinara, Reino, and Sant'Arcangelo Trimonte. These towns sustained heavy damage, with at least 90% of all structures affected. More than 50% of the total buildings affected were a total loss due to the severity of damage or complete destruction. Nearly twenty people died and 16,000 were made homeless. [7]

Aftermath

The town of Apice, abandoned after the earthquake. Apice vecchio - strada.jpg
The town of Apice, abandoned after the earthquake.

The Council of Ministers, allocated 2 billion Italian liras for first responders and 400 million for assistance. More than 20,000 tents were erected over a period of next ten days for the homeless. Significant quantities of medical supplies, food and clothing were distributed. More than 2,000 barracks were constructed by civil and military engineers to house homeless. [7]

After the earthquakes, there were concerns about the potential for landslides as the shocks had destabilized ground conditions on the nearby hills. As a result, authorities decided to evict the residents of Melito Irpino and Apice. [7] The old medieval Melito Irpino is currently a ghost town. [8]

See also

Related Research Articles

In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock. Large earthquakes can have hundreds to thousands of instrumentally detectable aftershocks, which steadily decrease in magnitude and frequency according to a consistent pattern. In some earthquakes the main rupture happens in two or more steps, resulting in multiple main shocks. These are known as doublet earthquakes, and in general can be distinguished from aftershocks in having similar magnitudes and nearly identical seismic waveforms.

A foreshock is an earthquake that occurs before a larger seismic event – the mainshock – and is related to it in both time and space. The designation of an earthquake as foreshock, mainshock or aftershock is only possible after the full sequence of events has happened.

Two earthquakes hit the Italian regions of Molise and Apulia on 31 October at 10:32:58 (UTC) and 1 November at 15:09:00 (UTC). The shocks had magnitudes of 5.9 and 5.8 Mw respectively. Most of the victims were killed and injured when a school collapsed in the town of San Giuliano di Puglia: 26 of the 51 schoolchildren died, together with one of their teachers. In particular, none of the nine children in the school's 4th Year survived.

<span class="mw-page-title-main">1915 Avezzano earthquake</span> Earthquake in Italy

The 1915 Avezzano earthquake or 1915 Fucino earthquake occurred on 13 January in central Italy at 07:52:42 local time. The shock had a moment magnitude of 6.7 and a maximum Mercalli intensity of XI (Extreme). The epicenter was located in the city of Avezzano in the Province of L'Aquila. Around 30,000 direct fatalities and $60 million in damage resulted from the earthquake.

Striking southern Italy on 8 September, the 1905 Calabria earthquake had a moment magnitude of 7.2 and a maximum Mercalli intensity of XI (Extreme). The first major earthquake of the 20th century, it severely damaged parts of Lipari, Messina Province and a large area between Cosenza and Nicotera and killed between 557 and 2,500 people.

The 1694 Irpinia–Basilicata earthquake occurred on 8 September. It caused widespread damage in the Basilicata and Apulia regions of what was then the Kingdom of Naples, resulting in more than 6,000 casualties. The earthquake occurred at 11:40 UTC and lasted between 30 and 60 seconds.

The 1986 Chalfant Valley earthquake struck southern Mono County near Bishop and Chalfant, California at 07:42:28 Pacific Daylight Time on July 21. With a moment magnitude of 6.2 and a maximum Mercalli intensity of VI (Strong), the shock injured two people and caused property damage estimated at $2.7 million in the affected areas. There was a significant foreshock and aftershock sequence that included a few moderate events, and was the last in a series of three earthquakes that affected southern California and the northern Owens Valley in July 1986.

The 1968 Belice earthquake sequence took place in Sicily between 14 and 15 January. The largest shock measured 5.5 on the moment magnitude scale, with five others of magnitude 5+. The maximum perceived intensity was X (Extreme) on the Mercalli intensity scale. The earthquake sequence, centred between the towns of Gibellina, Salaparuta and Poggioreale, killed at least 231 people, possibly more than 400, with between 632 and about 1,000 injured and left 100,000 homeless. It is known in Italy as Terremoto del Belice.

<span class="mw-page-title-main">1930 Irpinia earthquake</span> July 1930 earthquake in Southern Italy

The 1930 Irpinia earthquake occurred at 00:08 UTC on 23 July, chiefly in an area known as Irpinia. It had a surface-wave magnitude of 6.6 and a maximum intensity of X . The event caused 1,404 deaths and 4,624–7,000 injuries. The epicenter was near the boundaries between the regions of Basilicata, Apulia, and Campania.

<span class="mw-page-title-main">2011 Lorca earthquake</span> Moderate 5.1 Mw earthquake in Spain

The 2011 Lorca earthquake was a moderate 5.1 Mw earthquake that occurred 6:47 p.m. CEST on 11 May 2011, near the town of Lorca, causing significant localized damage in the Region of Murcia, Spain, and panic among locals, and displacing many from their homes. The quake was preceded by a magnitude 4.4 foreshock at 17:05, that inflicted substantial damage to many older structures in the area, including the historical Espolón Tower of Lorca Castle, the Hermitage of San Clemente and the Convent of Virgen de Las Huertas. Three people were killed by a falling cornice. A total of nine deaths have been confirmed, while dozens are reported injured. The earthquake was the worst to hit the region since a 5.0 Mw tremor struck west of Albolote, Granada in 1956.

The 1511 Idrija earthquake occurred on 26 March 1511 with a moment magnitude of 6.9 and a maximum EMS intensity of X. The epicenter was near the town of Idrija, although some place it in Friuli. The earthquake affected a large territory between Carinthia, Friuli, present-day Slovenia and Croatia. An estimated 3,000 people were killed and damage was considered severe. The earthquake was felt as far as in Switzerland and present-day Slovakia. A number of castles and churches were razed to the ground in a large area from northeast Italy to western Croatia.

The 1990 Gonghe earthquake occurred on April 26 at 17:37 China Standard Time in Hainan Tibetan Autonomous Prefecture, Qinghai Province. The mainshock had a surface wave magnitude of 7.0 Ms  and a moment magnitude of 6.5 Mw . It was presaged by two foreshocks that struck merely seconds before the main earthquake. On the Mercalli intensity scale, the earthquake had a rating of IX (Violent).

The 1995 Menglian earthquake or 1995 Myanmar–China earthquake occurred on 12 July at 05:46:43 local time in the Myanmar–China border region. The earthquake had an epicenter on the Myanmar side of the border, located in the mountainous region of Shan State. It registered 7.3 on the Chinese surface wave magnitude scale (Ms ) and 6.8 on the moment magnitude scale (Mw ). With a maximum Mercalli intensity assigned at VIII, it killed 11 people and left another 136 injured. Over 100,000 homes in both countries were destroyed and 42,000 seriously damaged. Some damage to structures were also reported in Chiang Mai and Chiang Rai, Thailand. The low death toll from this earthquake was attributed to an early warning issued prior to it happening. Precursor events including foreshocks and some seismic anomalies led to an evacuation of the area before the mainshock struck. It is thought to be one of the few successfully predicted earthquakes in history.

The 1990 Carlentini earthquake occurred off the Sicilian coast, 20 km east northeast from the town of Augusta, Sicily on 13 December at 01:24 local time. The moderately-sized earthquake measuring 5.6 on the moment magnitude scale (Mw ) resulted in the deaths of 19 people and caused at least 200 injuries. It also inflicted significant damage in the region, leaving 2,500 homeless.

The 1998 Azores Islands earthquake struck with an epicenter in the Atlantic Ocean, off the Azores Islands of Portugal at 05:19 local time. The 10 km (6.2 mi) deep mainshock, which measured 6.1 on the moment magnitude scale caused significant damage on Faial Island. At least 10 people died, 100 were injured, and 2,500 people were left without homes.

The 2016 Alboran Sea earthquake struck offshore, north northeast of Al Hoceïma, Morocco in the Strait of Gibraltar on 25 January at 04:22:02 UTC, or roughly 05:22:02 West Africa Time. At its strongest in the Alboran Sea, the earthquake measured 6.3–6.4 on the moment magnitude scale (Mw ) at a shallow hypocenter depth of 12 km (7.5 mi). Assigned a maximum Modified Mercalli scale intensity of VI (Strong), the earthquake caused one fatality, injuries to at least 30 persons, and moderate damage in Morocco and Spain.

On December 5, 1456, the largest earthquake to occur on the Italian Peninsula struck the Kingdom of Naples. The earthquake had an estimated moment magnitude of Mw  7.19–7.4, and was centred near the town of Pontelandolfo in the present-day Province of Benevento, southern Italy. Earning a level of XI (Extreme) on the Modified Mercalli intensity scale, the earthquake caused widespread destruction in central and southern Italy. Estimates of the death toll range greatly with as many as 70,000 deaths reported. It was followed by two strong Mw  7.0 and 6.0 earthquakes to the north on December 30. The earthquake sequence is considered the largest in Italian history, and one of the most studied.

The 1706 Abruzzo earthquake, also known as the Maiella earthquake, occurred on November 3 at 13:00 CEST. The earthquake with a possible epicenter in the Central Apennine Mountains (Maiella), Abruzzo had an estimated moment magnitude of 6.6–6.84 Mw . It was assigned a maximum Mercalli intensity of XI (Extreme), causing tremendous destruction in Valle Peligna. At least 2,400 people were killed.

The 1977 Bob–Tangol earthquake struck Kerman province of Iran on December 20, 1977, at 03:04 Iran Standard Time. The earthquake measured Mw 5.9 and struck at a depth of 22.7 km (14.1 mi). A maximum Modified Mercalli intensity of VII was evaluated based on damage. It had a strike-slip focal mechanism, which was unusual as the source structure was a thrust fault. It was part of a sequence of strong earthquakes along the 400 km (250 mi) Kuh Banan Fault. Between 584 and 665 people perished while a further 500–1,000 were injured; thousands were also made homeless. Casualties from the earthquake was considered moderate due to the sparsely populated area it affected. Preceded by foreshocks the month before, many residents became wary of a larger earthquake and took refuge outside their homes, contributing to the moderate death toll. However, there were none immediately before the mainshock so many were still in their homes when it struck. Aftershocks were felt for several months, some causing additional damage.

In 1990, present day South Sudan was rocked by a series of violent earthquakes. It started with the largest event (Mw 7.2), and continued with multiple very large aftershocks for the next couple of months. The earthquake sequence ruptured over a length of 50 km (31 mi). It contains some of the largest recorded earthquakes anywhere in Africa.

References

  1. 1 2 3 Rob, Westaway (1987). "The Campania, southern Italy, earthquakes of 1962 August 21". Geophysical Journal International. 88 (1). Oxford University Press: 1–24. Bibcode:1987GeoJ...88....1W. doi: 10.1111/j.1365-246X.1987.tb01366.x .
  2. 1 2 Rovida A.; Locati M.; Camassi R.; Lolli B.; Gasperini P. (2020). "The Italian earthquake catalogue CPTI15". Bulletin of Earthquake Engineering. 18 (7): 2953–2984. Bibcode:2020BuEE...18.2953R. doi:10.1007/s10518-020-00818-y. S2CID   212732483.
  3. 1 2 3 4 Paola Vannoli; Fabrizio Bernardi; Barbara Palombo; Gianfranco Vannucci; Rodolfo Console; Graziano Ferrari (2016). "New constraints shed light on strike-slip faulting beneath the southern Apennines (Italy): The 21 August 1962 Irpinia multiple earthquake". Tectonophysics . 691. Elsevier: 375–384. Bibcode:2016Tectp.691..375V. doi:10.1016/j.tecto.2016.10.032.
  4. ↑ D'Agostino N.; Mantenuto S.; D'Anastasio E.; Avallone A.; Barchi M.; Collettini C.; Radicioni F.; Stoppini A.; Fastellini G. (2009). "Contemporary crustal extension in the Umbria–Marche Apennines from regional CGPS networks and comparison between geodetic and seismic deformation" (PDF). Tectonophysics. 476 (1–2): 3–12. Bibcode:2009Tectp.476....3D. doi:10.1016/j.tecto.2008.09.033.
  5. ↑ Akinci, A.; Galadini, F.; Pantosti, D.; Petersen, M.; Malagnini, L.; Perkins, D. (6 April 2009). "Effect of Time Dependence on Probabilistic Seismic-Hazard Maps and Deaggregation for the Central Apennines, Italy". The Bulletin of the Seismological Society of America. 99 (2A). Seismological Society of America: 585. Bibcode:2009BuSSA..99..585A. doi:10.1785/0120080053. Archived from the original on 10 April 2009. Retrieved 6 April 2009.
  6. 1 2 Aldo Piombino; Filippo Bernardini; Gregorio Farolfi (2021). "Assessing Current Seismic Hazards in Irpinia Forty Years after the 1980 Earthquake: Merging Historical Seismicity and Satellite Data about Recent Ground Movements". Geosciences. 11 (4): 168. Bibcode:2021Geosc..11..168P. doi: 10.3390/geosciences11040168 .
  7. 1 2 3 "I terremoti del '900: Il terremoto del 21 agosto 1962 nell'Appennino campano" (in Italian). National Institute of Geophysics and Volcanology. 20 August 2012. Retrieved 2 March 2022.
  8. ↑ (in Italian) Melito Irpino on paesifantasma.it (Italian ghost towns website)
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.