1986 Kalamata earthquake
  | |
| UTC time | 1986-09-13 17:24:31 |
|---|---|
| ISC event | 486403 |
| USGS-ANSS | ComCat |
| Local date | 13 September 1986 |
| Local time | 20:24 EET |
| Magnitude | 5.9 Mw |
| Depth | 12.5 km (7.8 mi) |
| Epicenter | 37°00′50″N 22°10′34″E / 37.014°N 22.176°E |
| Type | Normal |
| Areas affected | Greece |
| Max. intensity | MMI X (Extreme) |
| Casualties | 20–24 dead, 330 injured |
The 1986 Kalamata earthquake struck the southern Peloponnese Region of Greece on September 13 at 20:24 local time. The 12.5 km (7.8 mi) deep moment magnitude (Mw ) 5.9 earthquake had an epicenter near the coastal city of Kalamata[1] and was assigned X (Extreme) on the Mercalli intensity scale. The earthquake was the result of normal faulting along a northwest-dipping fault and produced surface ruptures. Extensive damage was reported in Kalamata and Elaiochori.[2] At least 20 people died and 330 were injured. Survivors sought refuge at campsites and reconstruction work lasted five years.
Tectonic setting
[edit]Greece is a seismically active country located in a complex zone of interaction between the African plate the Aegean Sea. Along the Hellenic arc, the African plate subducts beneath the Aegean Sea at around 40 mm (1.6 in) per year. Shallow-focus earthquakes of less than 50 km (31 mi) depth are common—the result of accommodating convergence via subduction-related deformation. Back-arc extension occurs within the Aegean Sea, above the subducting crust, causing normal and strike-slip faulting earthquakes. Large intermediate-depth earthquakes occur due to deformation within the subducting plate.[3] The Peloponnese region is characterized by active extensional tectonics which has continued since the Pliocene. Present-day extension occurs in an east–west direction, accommodated by active north–south striking normal faults.[4]
Kalamata is located at the border between the valley of Messinia and the Messenian Gulf which forms a graben. To the east is the Taygetus mountain range; separating it from the graben is a series of normal dip-slip faults, which are part of a seismic zone in West Mani. These faults generally trend north–south and accommodates east–west extension.[5] One of them is the Kalamata Fault which strikes north northeast–south southwest and dips northwest at 70–80°.[6] The Kalamata Fault is part of a group of west-dipping faults that separates the Taygetus mountains from the Pamisos river plain.[7] Believed to have formed during the Quaternary, it was not associated with any earthquakes or surface ruptures prior to 1986.[4] The region frequently experience earthquakes and their associated tsunamis and liquefaction such as in 1867 and 1947.[8]
Earthquake
[edit]The earthquake, with a moment magnitude of 5.9, originated at a depth of 12.5 km (7.8 mi). The timing of occurrence was at 20:24 EET on 13 September.[1] It was caused by normal faulting along a north-northeast–south-southwest striking and west–northwest dipping fault.[9] The causative fault was later known as the Kalamata Fault; the rupture of the fault occurred across an area estimated at 15 by 10 km (9.3 by 6.2 mi).[10] The fault ruptured to the surface along its northern extent, causing surface ruptures.[4]
Surface rupture
[edit]Small fault scarps and surface ruptures were observed 2–3 km (1.2–1.9 mi) east of Kalamata and aligned with a known fault.[6] These were reported for 15–18 km (9.3–11.2 mi) along a north-northeast–south-southwest trend,[11] and were intermittently accompanied by a fissure. One of these ruptures was mapped continuously for 4.5 km (2.8 mi). Some ruptures measured up to 6–18 cm (2.4–7.1 in) in vertical height and were 2–6 cm (0.79–2.36 in) wide.[12] They often appeared in terraced olive groves near rocky outcrops, and were several tens of centimeters west of a large fault surface.[12][10] Heavy damage occurred in homes where the surface rupture propagated beneath.[11]
The most significant surface rupture occurred within an existing north-northeast trending fault trace in the Mesozoic limestone in Elaiochori and Perivolakia. It exhibited a vertical displacement of 10 cm (3.9 in) on the northwest side of the fault, horizontal heave of 5–15 cm (2.0–5.9 in), and left-lateral offset of 3 cm (1.2 in). The occurrence of unconsolidated breccia suggest the same fault has reactivated in past earthquakes.[11]
Strong ground motion
[edit]| Modified Mercalli intensities in selected locations[2] | |
| MMI | Locations |
|---|---|
| MMI X (Extreme) | Elaiochori, Perivolakia |
| MMI VIII (Severe)–MMI VII (Very strong) | Kalamata, Verga, Poliani, Aris, Artemisia, Nedousa |
| MMI VI (Strong)–MMI V (Moderate) | Achladochori, Chelidoni, Ampheia, Kampos, Andritsaina-Krestena, Goumero, Makrisia |
Two accelerographs in Kalamata recorded a maximum peak ground acceleration (pga) of 0.27 g in the horizontal component.[10] Meanwhile, the pga in the veritcal component was 0.368 g.[13] Pga exceeding 0.1 g lasted 2.5 seconds while the maximum horizontal velocity was 32.3 cm (12.7 in) per second.[14] The greater Kalamata and Elaiochori regions were within the meizoseismal area.[8]
Downtown Kalamata experienced Modified Mercalli intensity VIII (Severe), where damage was heavy; 42 percent of homes were obliterated or had irreparable damage. In Elaiochori and Perivolakia, the Modified Mercalli intensity was X (Extreme) and both villages were razed. The earthquake produced seismic waves with a short period of 0.15–1.6 seconds, affecting short and poorly built structures. Buildings in Elaiochori were poorly constructed and without retrofitting, could not endure the shaking.[13]
Aftershocks
[edit]Following the mainshock, seismic instruments were installed by the National Observatory of Athens, University of Athens, Institut de Physique du Globe de Paris and Grenoble Observatory. These instruments allowed scientists to determine the focal mechanism and depth of aftershocks. About 740 aftershocks were recorded in the first two weeks after the mainshock. Most aftershocks had focal mechanisms consistent with the mainshock (normal) while some were dextral strike-slip events on a fault perpendicular to the mainshock source.[4] The largest aftershock on 15 September measured Ms 5.3 and occurred south of the mainshock.[10] It had a maximum intensity of VII (Very strong),[15] caused 37 injuries, and further damage in Kalamata.[16]
These aftershocks were distributed across a 15 km (9.3 mi) × 10 km (6.2 mi) zone in two distinct clusters; north and south, separated by a zone without any. The gap measured 2 km (1.2 mi) and extended to a depth of 8 km (5.0 mi). The lack of seismicity in the gap was the result of smooth rupturing along the fault.[17] At 9–10 km (5.6–6.2 mi) depth, the two aftershocks clusters merged. These aftershocks had focal depths up to 10 km (6.2 mi) deep but none originated beyond 12 km (7.5 mi). The southern sequence initiated immediately following the mainshock at the southern extension of the Kalamata Fault, releasing strain that still remained. The northern aftershock swarm experienced greater activity.[4]
Impact
[edit]
The earthquake caused €670 million in damage.[18] At least 20 people died;[19] more deaths were prevented because most residents attended a ferry line opening ceremony when the earthquake occurred.[20] Six bodies were recovered from a five-story reinforced concrete apartment that collapsed. Six people died from falling debris; one person was crushed, one died from a heart attack, an infant died from suffocation and another from serious injuries.[21] Three individuals perished when the Holy Monastery of Velanidia's defensive towers collapsed.[22] Four people died when an old stone building collapsed in Elaiochori. An additional 330 people were injured including 83 with serious injuries.[23]
In Kalamata, four buildings were razed, and of the 9,124 buildings in the city, at least 20 percent sustained damage so extreme that they were demolished. Another 16 percent of buildings were heavily damaged, and in the other 36 percent, damage was moderate.[24][25] Forty-four reinforced concrete buildings had to be torn down. An additional 289 mixed and 1,931 load-bearing masonry structures were also demolished.[26] At a jetty, cracks up to 10 cm (3.9 in) wide were reported and parts of its walls partially detached. Power outages occurred and communication services were disrupted in the city.[23] Some rockfalls occurred in the Taygetus mountains, obstructing a major road that linked Kalamata to Sparta.[27][28]
The Metropolitan Church of Ypapanti was heavily damaged and had to be restored,[29] while the dome and roof of the Church of Agioi Apostoloi collapsed.[30] Structures such as bridges and industrial facilities sustained little damage or were unaffected.[23] At Elaiochori, located 7 km (4.3 mi) from Kalamata, at least 70 percent of its buildings were destroyed, leaving only 120 intact.[13] Extreme damage also occurred in the villages of Verga, Poliani, Aris, Artemisia and Nedousa.[23]
Aftermath
[edit]Rescuers immediately attended to two buildings in Kalamata; a collapsed apartment and another two-storey house where two people were trapped. They were accompanied by members of the Greek Army, Police and Fire Service. Rescuers pulled four survivors from the apartment building immediately. Another seven people were rescued the following afternoon. Rescue efforts were disrupted by curious onlookers, friends and family members of those trapped visiting the site.[31] Rescue teams from France and Germany also assisted.[32] For the next five years, basic infrastructure were reconstructed under strict seismic codes. Many displaced individuals sought refuge across 30 campsites while their homes were reconstructed, while some left the city for other areas such as Athens.[33]
In 1987, Prime Minister Andreas Papandreou did not attend a memorial ceremony on the one-year anniversary of the earthquake, citing his busy schedule.[34] Instead, he boarded a cruise with Dimitra Liani which sparked anger among the public.[34][35]
See also
[edit]References
[edit]- ^ a b ISC (27 June 2022), ISC-GEM Global Instrumental Earthquake Catalogue (1900–2009), Version 9.1, International Seismological Centre
- ^ a b "Event 486403 Southern Greece". ISC Bulletin: event catalogue search. International Seismological Centre. doi:10.31905/D808B830. Retrieved 3 July 2021.
- ^ Matthew W. Herman; Gavin P. Hayes; Gregory M. Smoczyk; Rebecca Turner; Bethan Turner; Jennifer Jenkins; Sian Davies; Amy Parker; Allison Sinclair; Harley M. Benz; Kevin P. Furlong; Antonio Villaseñor (2015). "Seismicity of the Earth 1900‒2013 Mediterranean Sea and vicinity" (Open-File Report 2010-1083-Q). Open-File Report. United States Geological Survey. doi:10.3133/ofr20101083Q. Retrieved 11 August 2021.
- ^ a b c d e Lyon-Caen et al. 1988.
- ^ Lyon-Caen et al. 1988, p. 14,969.
- ^ a b Papazachos et al. 1988, p. 56.
- ^ Lyon-Caen et al. 1988, p. 14,972.
- ^ a b S. Stiros; V. Kontogianni (2008). "Modelling of the 1986 Kalamata (SW Greece) earthquake faulting using geodetic data". Journal of Applied Geodesy. 2 (3). De Gruyter: 179. Bibcode:2008JAGeo...2..179S. doi:10.1515/JAG.2008.020. S2CID 128641270.
- ^ Papazachos et al. 1988, p. 55.
- ^ a b c d Jean-Christophe Gariel; Pierre-Yves Bard; Kyriazis Pitilakis (1991). "A theoretical investigation of source, path and site effects during the 1986 Kalamata earthquake (Greece)". Geophysical Journal International. 104 (1): 165–177. Bibcode:1991GeoJI.104..165G. doi:10.1111/j.1365-246X.1991.tb02502.x.
- ^ a b c Papazachos et al. 1988, p. 59.
- ^ a b Lyon-Caen et al. 1988, p. 14,969–14,974.
- ^ a b c Nikolaos Theofanopoulos; Kazuo Dan (1988). "Simulation of the ground motion at Kalamata City – Greece" (PDF). Proceedings of Ninth World Conference on Earthquake Engineering. 2. Japan.
- ^ Pomonis, A.; Gaspari, M.; Karababa, F. S. (June 2014). "Seismic vulnerability assessment for buildings in Greece based on observed damage data sets". Bulletin of Geophysics and Oceanography. 55 (2): 501–534. doi:10.4430/bgta0069. Archived from the original on 15 September 2022. Retrieved 15 September 2022.
- ^ National Geophysical Data Center (1972). "National Geophysical Data Center / World Data Service (NGDC/WDS): NCEI/WDS Global Significant Earthquake Database. NOAA National Centers for Environmental Information". NOAA National Centers for Environmental Information. doi:10.7289/V5TD9V7K.
- ^ "M 4.9 – 6 km NW of Kardamýli, Greece". United States Geological Survey. Retrieved 3 July 2021.
- ^ Papazachos et al. 1988, p. 64.
- ^ Ioannis Kassaras; D. Kazantzidou-Firtinidou; Vasilis Kapetanidis; A Ganas (2018). "Seismic risk and loss assessment for Kalamata (SW Peloponnese, Greece) from neighbouring shallow sources" (PDF). Bollettino di Geofisica Teorica ed Applicata. 59 (1). doi:10.4430/bgta0222. Archived from the original (PDF) on 2021-08-11. Retrieved 2021-08-11.
- ^ Laube, Jerri (1987), Kalamata Earthquake, 1986: Psychological reactions and roles for health care workers (Report), Louis de la Parte Florida Mental Health Institute
- ^ Hope, Kerin (14 September 1986). "Death Toll Rises in Kalamata Earthquake". Associated Press News. Kalamata, Greece. Retrieved 3 July 2021.
- ^ Liakogonas, V. (13 September 2021). "Καλαμάτα – 13 Σεπτεμβρίου 1986: Όταν τα 6,2 ρίχτερ διέλυσαν την πόλη – 35 χρόνια μετά από τον καταστροφικό σεισμό (video, φωτογραφίες)" [Kalamata – September 13, 1986: When the 6.2 magnitude earthquake destroyed the city ― 35 years after the devastating earthquake (video, photos)]. ERT News (in Greek). Retrieved 1 October 2022.
- ^ "Ιερά Μονή Βελανιδιάς – Το ιστορικό αλλά και... πολύπαθο μοναστήρι της Μεσσηνίας (Βίντεο)". Εφημερίδα Ελευθερία. 21 May 2018. Retrieved 11 August 2021.
- ^ a b c d S. A. Anagnostopolous; D. Rinaldis; V. A. Lekidis; V. N. Margaris; N. P. Theodulidis (1987). "The Kalamata, Greece, Earthquake of September 13, 1986". Earthquake Spectra. 3 (2): 365–402. Bibcode:1987EarSp...3..365A. doi:10.1193/1.1585434. S2CID 128902740. Retrieved 3 July 2021.
- ^ Papazachos, B.; Papazachos, K. (1989). Οι σεισμοί της Ελλάδας [The earthquakes of Greece] (in Greek). Ziti Publications.
- ^ Papazachos, B.C.; Papazachou, C. (1997). The earthquakes of Greece. Ziti Publications.
- ^ Argyrakis, K. (1987). Αξιολόγηση ζημιών των σεισμών 1986 της Καλαμάτας [Damage assessment of the 1986 Kalamata earthquakes] (PDF) (Report) (in Greek). Earthquake Planning and Protection Organization. Archived from the original (PDF) on 2022-10-01. Retrieved 2022-10-01.
- ^ "Καλαμάτα 1986 (ΙΧ)" (in Greek). Earthquake Planning and Protection Organization. Retrieved 11 August 2021.
- ^ "Εκδήλωση μνήμης για τα 32 χρόνια από τους σεισμούς του 1986". kalamata.gr (in Greek). 2018. Retrieved 11 August 2021.
- ^ "Church of Ypapanti". greece.terrabook.com. TerraBook. Retrieved 11 August 2021.
- ^ "Church of Agioi Apostoloi (Church of the Holy Apostles)". Atlas Obscura. Retrieved 11 August 2021.
- ^ Diamantis, Y. T. (13 September 2022). "Σεισμός Καλαμάτας 1986: Ερείπια, τρόμος και θάνατος" [Kalamata Earthquake 1986: Ruins, terror and death]. In.gr (in Greek). Retrieved 1 October 2022.
- ^ "Σεισμός: 13 Σεπτεμβρίου 1986 – Η ημέρα που ο Εγκέλαδος κατέστρεψε την Καλαμάτα" [Earthquake: September 13, 1986 – The day Enceladus destroyed Kalamata]. taNea (in Greek). 13 September 2019. Retrieved 1 October 2022.
- ^ Perdikea, M. (1 October 2022). "13 Σεπτεμβρίου 1986: 35 χρόνια από τον φονικό σεισμό της Καλαμάτας" [September 13, 1986: 35 years since the deadly Kalamata earthquake]. Messinia Live (in Greek). Retrieved 1 October 2022.
- ^ a b Kaplan, Robert D. (1994). Balkan Ghosts, A Journey Through History. London: Vintage Books. pp. 273–274. ISBN 0679749810.
- ^ "Top Greek tries an old trump: bases". Chicago Tribune. 16 November 1987.
Sources
[edit]- Lyon-Caen, H.; Armijo, R.; Drakopoulos, J.; Baskoutass, J.; Delibassis, N.; Gaulon, R.; Kouskouna, V.; Latoussakis, J.; Makropoulos, K.; Papadimitriou, P.; Papanastassiou, D.; Pedotti, G. (1988). "The 1986 Kalamata (South Peloponnesus) Earthquake: Detailed study of a normal fault, evidences for east-west extension in the Hellenic Arc". Journal of Geophysical Research: Solid Earth. 93 (B12): 14967–15000. Bibcode:1988JGR....9314967L. doi:10.1029/JB093iB12p14967. S2CID 129434743. Retrieved 3 July 2021.
- Papazachos, B.; Kiratzi, A.; Karacostas, B.; Panagiotopoulos, D.; Scordilis, E.; Mountrakis, D. M. (1988). "Surface fault traces, fault plane solution and spatial distribution of the aftershocks of the September 13, 1986 earthquake of Kalamata (Southern Greece)". Pure and Applied Geophysics. 126 (1): 55–68. Bibcode:1988PApGe.126...55P. doi:10.1007/BF00876914. S2CID 128953390.
Further reading
[edit]- Ioannis g. Fountoulis; Spyridon d. Mavroulis (2014). "Application of the Environmental Seismic Intensity scale (ESI 2007) and the European Macroseismic Scale (EMS-98) to the Kalamata (SW Peloponnese, Greece) earthquake (Ms=6.2, September 13, 1986) and correlation with neotectonic structures and active faults". Annals of Geophysics. 56 (6). doi:10.4401/ag-6237. ISSN 2037-416X. S2CID 127327874.
