1954 Sofades earthquake

The 1954 Sofades earthquake event struck central Greece on April 30, 1954 16:02 (UTC+3). The tremor was recorded with magnitudes ranging from 6.7−7.0 Mw and intensity X (Extreme) as the highest recorded on the Modified Mercalli Intensity scale. More than 25 people were killed, 717 suffered injuries and about 28,000 structures were damaged or completely destroyed.[2][3][4]

1954 Sofades earthquake
UTC time1954-04-30 13:02:39
ISC event890584
USGS-ANSSComCat
Local dateApril 30, 1954
Local time16:02:39 (UTC+3)
Magnitude6.7−7.0 Mw
Depth10.0 km
Epicenter39.228°N 22.162°E / 39.228; 22.162
FaultLeontari-Anavra Fault Zone
TypeStrike-slip
Areas affectedKarditsa, Larissa, Trikala, Phthiotis, Magnesia and Evritania Prefectures
Total damage$3.15 million (1954 rate)
Max. intensityX (Extreme)
Aftershocks5.8 Mw[1]
Casualties25+ deaths, 717 injuries

Geological setting

The location of the areas mostly afflicted from the tremor was situated in the southern parts of the western Thessalian Plain, a late Caenozoic extensional basin. The basin is filled with late fluvio-terrestrial deposits as thick as 500 meters. These plains were formed from the post-orgenic collapse of the first extensional phase in the Late Miocene–Pliocene period. The first trended NE-SW and the second phase trended N-S during the Mid-Pleistocene periods that then activated the E-W and ENE-WSW striking faults in the region. The hills that surround the plains are with Alpine like formations of the Pelagonian, Pindos and Koziakas/Western Greece geotectonic units made up of mostly limestone and undated Molassic sediments.[5]

Leontari-Anavra Fault Zone

The Leontari-Anavara Fault zone is the most dominantly active Quaternary fault zone of the Western Thessaly plain region. The fault zone consists of four linked segments, the Kedros, Leontari, Velesiotes and Thaumako, all dipping Northward and an en echelon arrangement trending ENE-WSW. the separate segments were about 5000−7000 meters in length, with a combined total length of about 25 kilometers. Continuing seismic activity along the fault even after the quake has led to the creation of a multiple-scarp footwall morphology, some observed near and on the Enipeas river[5][6] and it has also produced later tremors, one of them being the 2021 Larissa earthquake that led to the death of one person and summoned severe damage to multiple villages and towns. The earthquake was also said to have been part of the episodic pattern of tremors that have been produced in the area over the years.[7] Another example is the 1957 Velestino earthquake which was produced in the same basin but far on the other side of the LAFZ. Despite that it bears similarities and characteristics to the 1954 Sofades event.[8][6]

The Enipeas, Domokos, Vouzi, Farsala and Narthaki faults constitute principal E-W trending fault zone with similar characteristics and kinematics to those of the eastern part. More precisely, a dominant strike-slip striation corresponding to a dextral strike slip motion has been recognized along the fault slickensides to be super imposed by two oblique to dip-slip striations corresponding respectively to two normal reactivations.[6]

Earthquake

The earthquake struck at 4 o'clock in the afternoon with initial magnitudes of 6.7 in the moment magnitude scale, it was later revised to a 7.0, however some sources have continued to stick with a magnitude of 6.7 or 6.8 in magnitude. For the intensity it ranged from intensity IX (Violent) to X (Extreme) in the Modified Mercalli Intensity scale or simply termed as the MMI.[3] The largest possible foreshock that was recorded was a miniature earthquake of 4.6 Mw as documented, and the largest aftershock was a magnitude 5.8 Mw tremor with an intensity of only about VI (Strong) according to the United States Geological Survey.[9]

Impact

Numerous damage was observed mostly in the Thessalian Plain, specifically in the prefectures of Karditsa, Larissa, Trikala, Phthiotis, Magnesia and Evritania. The villages of Paschalitsa, Neo Ikonio, Asimochori, Fyllo, Grammatiko and Othomaniko among others suffered severe to complete damage. The villages near the epicenter also suffered major effects such as Liquefaction which is the softening of the ground similar to liquid, this was possibly due to the soft sedimentary rocks that comprise the Thessalian plains and the large scale intensities recorded in the regions. Another common effect in earthquakes that was also observed in the nearby regions was surface ruptures, mostly from the fault lines that triggered the tremor. The longest of the surface ruptures was 5 kilometers in length, which also interrupted and disrupted an entire train line connecting the villages and to the other regions.[3]

Overall records say the tremor caused $3.15 or 100 million Francs (1954 rate) in damages. In damages, about 28,000 structures and houses sustained damages, 6,599 of which were actually damaged. 25−31 people died and 717 people were injured.[3][4][10]

See also

References
  1. "M 5.8 - 6 km SSE of Kallifóni, Greece". earthquake.usgs.gov. USGS–ANSS. Retrieved 31 October 2021.
  2. "M 6.7 - 7 km NE of Anávra, Greece". earthquake.usgs.gov. Archived from the original on 2021-02-03. Retrieved 2021-10-31.
  3. "Σοφάδες 1954 (IX) | Ο.Α.Σ.Π." www.oasp.gr. Retrieved 2021-10-31.
  4. "M 6.7 - 7 km NE of Anávra, Greece - Impact". earthquake.usgs.gov. Archived from the original on 2021-10-31. Retrieved 2021-10-31.
  5. Papathanassiou, George; Valkaniotis, Sotirios; Pavlides, Spyros (2007-01-01). "Applying the INQUA scale to the Sofades 1954, Central Greece, earthquake". 40. {{cite journal}}: Cite journal requires |journal= (help)
  6. "Field study of the southern Thessaly highly active fault zone". doczz.net. Retrieved 2021-10-31.
  7. Vallianatos, Filippos; Michas, Georgios; Hloupis, George (September 2021). "Seismicity Patterns Prior to the Thessaly (Mw6.3) Strong Earthquake on 3 March 2021 in Terms of Multiresolution Wavelets and Natural Time Analysis". Geosciences. 11 (9): 379. doi:10.3390/geosciences11090379.
  8. Papazachos, Giannis; Papazachos, Costas; Skarlatoudis, Andreas; Kkallas, Harris; Lekkas, Efthimios (2016-01-01). "Modelling macroseismic observations for historical earthquakes: the cases of the M = 7.0, 1954 Sofades and M = 6.8, 1957 Velestino events (central Greece)". Journal of Seismology. 20 (1): 151–165. doi:10.1007/s10950-015-9517-9. ISSN 1573-157X. S2CID 129650530.
  9. "M 5.8 - 6 km SSE of Kallifóni, Greece". earthquake.usgs.gov. Archived from the original on 2021-10-31. Retrieved 2021-10-31.
  10. Rothé, J. P. (1969). Rothe, J.P., 1969, The seismicity of the earth, 1953-1965: Paris, United Nations Educational, Scientific and Cultural Organization, 336 p. [Paris]: Unesco.
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