1967 Mudurnu earthquake
Encyclopedia
The 1967 Mudurnu earthquake or more correctly, the 1967 Mudurnu Valley earthquake occurred at about 16:57 GMT (18:57 local time) on July 22, 1967, near Mudurnu
, Bolu Province
, north-western Turkey
. The earthquake was one of a series of major and intermediate quakes that have occurred in modern times along the North Anatolian Fault
since 1939.
Although the Mudurnu Valley earthquake was relatively strong, there were only 86 fatalities, with 332 people injured. About 5,200 houses were destroyed or damaged beyond repair; some 900 of these were in Adapazari
at the far western end of the fault zone, and many collapsed completely as a result of aftershocks.
The surface rupture zone, which was between 1–4 kilometers wide, stretched some 80 kilometers from to Lake Abant to Sapanca
in an East-West direction, generally following the course of the Mudurnu River until it flows north near Lake Sapanca
. The earthquake is named after the river valley, not the town of Mudurnu
itself, which is some distance south of the river and outside the rupture zone.
Considering the large magnitude (7.1) and widespread surface rupturing, structural damage to buildings was surprisingly small; variations in damage were related to the materials used and construction method of individual buildings, rather than the proximity to the fault-break. Some villages suffered 70% destruction of property, while others nearby with fault lines running right through them had only a few houses damaged.
A number of small aftershocks occurred, mostly towards the westward end of the fault zone; its eastern end overlapped the rupture zone of a previous 7.1 earthquake (1957 Abant
) with a similar epicentre, by about 25Km.
The authors of the 1968 Unesco
report into the Mudurnu Valley earthquake (see Sources) felt that its intensity
was difficult to estimate accurately. In some places an implied level of XII was evident, whereas the vibrational effects were nearer VIII-IX (MM). Although a large number of sites were independently assessed by up to six observers, variations of up to four degrees of the (MM) scale indicated that an accurate figure was practically impossible to gauge.
Mudurnu
Mudurnu is a small town and a district of Bolu Province in the Black Sea region of Turkey, 52 km south-west of the city of Bolu. It covers an area of 1,349 km², and the population is 25,480 of which 6,000 live in the town of Mudurnu...
, Bolu Province
Bolu Province
Bolu Province is a province in north western in the Black Sea region of Turkey, midpoint between the large cities of Istanbul and Ankara. It covers an area of 7,410 km², and the population is 271,208....
, north-western Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
. The earthquake was one of a series of major and intermediate quakes that have occurred in modern times along the North Anatolian Fault
North Anatolian Fault
The North Anatolian Fault is a major active right lateral-moving strike-slip fault in northern Anatolia which runs along the transform boundary between the Eurasian Plate and the Anatolian Plate. The fault extends westward from a junction with the East Anatolian Fault at the Karliova Triple...
since 1939.
Although the Mudurnu Valley earthquake was relatively strong, there were only 86 fatalities, with 332 people injured. About 5,200 houses were destroyed or damaged beyond repair; some 900 of these were in Adapazari
Adapazari
Adapazarı is a city in northwestern Turkey and the capital of Sakarya Province. The province itself was originally named Adapazarı as well. Adapazarı is a part of the densely populated region of the country, known as the Marmara Region. As of 2010, the city has a population of 560,876 ...
at the far western end of the fault zone, and many collapsed completely as a result of aftershocks.
The surface rupture zone, which was between 1–4 kilometers wide, stretched some 80 kilometers from to Lake Abant to Sapanca
Sapanca
Sapanca is a town and district of Sakarya Province in the Marmara region of Turkey near the Lake Sapanca. The mayor is İbrahim Uslu .-External links:***...
in an East-West direction, generally following the course of the Mudurnu River until it flows north near Lake Sapanca
Lake Sapanca
Lake Sapanca is a fresh water lake in Turkey, between the Gulf of İzmit and the Adapazarı Meadow. The lake has a catchment area of 251 km², surface area is 45 km², a length 16 km east-west / 5 km north-south, and a maximum depth of 52 m.Lake Sapanca, Turkey...
. The earthquake is named after the river valley, not the town of Mudurnu
Mudurnu
Mudurnu is a small town and a district of Bolu Province in the Black Sea region of Turkey, 52 km south-west of the city of Bolu. It covers an area of 1,349 km², and the population is 25,480 of which 6,000 live in the town of Mudurnu...
itself, which is some distance south of the river and outside the rupture zone.
Considering the large magnitude (7.1) and widespread surface rupturing, structural damage to buildings was surprisingly small; variations in damage were related to the materials used and construction method of individual buildings, rather than the proximity to the fault-break. Some villages suffered 70% destruction of property, while others nearby with fault lines running right through them had only a few houses damaged.
A number of small aftershocks occurred, mostly towards the westward end of the fault zone; its eastern end overlapped the rupture zone of a previous 7.1 earthquake (1957 Abant
1957 Abant earthquake
The 1957 Abant earthquake occurred at 08:33 on 26 May. The earthquake had an estimated magnitude of 7.1 and a maximum felt intensity of IX on the Mercalli intensity scale, causing 52 casualties....
) with a similar epicentre, by about 25Km.
The authors of the 1968 Unesco
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...
report into the Mudurnu Valley earthquake (see Sources) felt that its intensity
Mercalli intensity scale
The Mercalli intensity scale is a seismic scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake, and is distinct from the moment magnitude M_w usually reported for an earthquake , which is a measure of the energy released...
was difficult to estimate accurately. In some places an implied level of XII was evident, whereas the vibrational effects were nearer VIII-IX (MM). Although a large number of sites were independently assessed by up to six observers, variations of up to four degrees of the (MM) scale indicated that an accurate figure was practically impossible to gauge.