April 14, 1928 Earthquake: Chirpan, Bulgaria

NOTE: The total effects are listed with the earthquake on 1928 April 14.

1928, April 14 and 18. On April 14 and 18, 1928, earthquakes of magnitude 6.75 originated in southern Bulgaria, resulting in what has been called the most serious earthquake calamity in the history of that country. The epicenter of the earlier shock was near Chirpan, where there was great destruction; that of the latter was somewhat farther west near Popovitsa (Papazli). Faults were produced with maximum throw of 3 to 4 meters. (ref #1006)

1928, April 14 to 18 [effects listed with April 14 event]. Intensity XI. Destruction of the towns of Plovdiv, Borisovgrad and Tchirpan and 240 villages. 105 killed, 74,750 houses destroyed, 264000 inhabitants without shelter (of a population of 488,000). Cracks in the ground, rails twisted. According to G. Bontcheff, the earthquake was local; its main cause lies in the instability of the masses which are at the base of the valley. (refe #1093)

1928, April 18, 19:22:48 UTC. 42.1 N, 25 E, magnitude 7.0, S. Bulgaria, intensity X (Philippoupole). The earthquake was preceded by foreshocks the largest of which occurred on 14 April (09:30, 42.15° N, 25.28° E, M = 6.8) and it was also destructive. It was followed by many aftershocks the largest of which occurred on 25 April (09:25:, M = 5.7). These earthquakes caused large destructions in Philippoupole, Tsipran and Papasli. In Philippoupole 8,000 houses collapsed. Totally 74,570 houses were overturned in 240 cities and villages. 127 people were killed and 1,735 were injured. During the generation of the earthquake of 14 April (M =6.8), two parallel normal faults were created in the ground with an east-west direction, a distance between them equal to about 15 km and a fall to the south side of the north fault and to the north side of the south fault by about 50 cm. The length of the north fault was equal to 38 km and of the south equal to 42 km. During the generation of the main shock (M = 7.0), the ground rupture was extended more to the west and turned to the northwest. The total length of the rupture which was caused by the main shock was about 60 km while the northeast side of the fault was sunk by more than 3m near the village Popovitsa. In Komotine the earthquake caused the collapse of a house and fissures in walls. In Thessaloniki, it caused panic and fissures in the walls of some houses and of some building in the beach. In the area of Kapoutzidi two houses collapsed. The inhabitants got out of the houses and many of them spent the night in the open air. In Eleutheroupole, the police station collapsed. It was felt in several places of Greece. Some days before the earthquake the mineral springs around Philippoupole overflowed and the water that came out was very warm (Newspaper of Balkans, 19.4.1928; AOA, 1932; Sieberg, 1932b; Montandon, 1953; Richter, 1958). Isoseismals for the largest foreshock, for the main shock and for its largest aftershock are cited in the atlas of UNESCO (Shebalin et al., 1974b) and by Papazachos et al. (1997b). (ref #4408)

1928, April 14, 08:59:43 UTC. 42.2 N, 25.3 E, depth 7 km, magnitude 6.8, intensity X. (ref #1004)

1928, April 14, 08:59:53 UTC. 42 N, 25 E, magnitude 6.75. (ref #130)

1928, April 14, 09:00:01.09 UTC. 42.402 N, 25.667 E, magnitude 6.8 unknown. (reference #9910)