Dr. Özalp is a geologist, a senior researcher in the General Directorate of Mineral Research and Exploration (MTA). He has worked for Geological Engineering Department as a Research Assistant (1992-1999) in Çukurova University. His interests are active tectonics, neotectonics, and paleoseismology. His recent project is focused on the Paleoseismological Research of Turkey. According to Google Scholar, he has more than 1300 citations with an h-index of 16.
Kita ici bir transform fay olan Kuzey Anadolu Fayi (KAF), Marmara Bolgesi’nde Kuzey ve Guney olma... more Kita ici bir transform fay olan Kuzey Anadolu Fayi (KAF), Marmara Bolgesi’nde Kuzey ve Guney olmak uzere iki ana kola ayrilir. Bandirma ve Dokurcun Vadisi arasinda Guney kol saga sicramali sekmelerle birbirinden ayrilan, dogudan batiya dogru Geyve, Iznik ve Gemlik olmak uzere uc ana fay segmentinden olusur. Fay segmentlerinin uzunlugu 40 ile 57 km arasinda degisir. GPS verileri Guney kolda yaklasik 5 mm/yil kayma hizi onermektedir. 40 km uzunlugundaki Gemlik segmenti uzerinde gerceklestirdigimiz paleosismolojik kazilarda iki yuzey faylanmasi olayi gozlenmistir. Bunlar 1857 ve 1419 tarihsel depremleri ile denestirilebilmektedir. Gemlik fayindaki son iki deprem arasindaki tekrarlanma araligi 438 yildir. Bulgular, Iznik fayinda varligi bilinen 1419 depremindeki yuzey faylanmasina Gemlik fayinin da dahil oldugunu ve bu depremde en az 95 km uzunlugunda cok segmentli yuzey faylanmasi gelistigini gostermektedir. 5 mm/yillik kayma hizina gore KAF’nin Iznik Golu ile Dokurcun vadisi arasinda kalan kesiminde 595 yilda biriken yer degistirme miktari yaklasik 3 metre olarak hesaplanmaktadir. Buna gore Kuzey Anadolu Fayi’nin Guney kolunun da en az Kuzey kol kadar buyuk deprem ureteme potansiyeline sahip oldugu soylenebilir
TEZ1222Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 1992.Kaynakça (s. 95-98) var.ix, 100 ... more TEZ1222Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 1992.Kaynakça (s. 95-98) var.ix, 100 s. : rnk. res., hrt. ; 30 cm.…Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi Tarafından Desteklenmiştir
The Gemlik Bay is located in the southeast part of Marmara Sea, where is one of the major active-... more The Gemlik Bay is located in the southeast part of Marmara Sea, where is one of the major active-faulting features seen in the NAF Zone. There are three sets of faults in and aroud the Gemlik Bay: 1) several south-dipping normal faults along southern coast of the Armtlu Peninsula 2) several continuous north-dipping normal faults along the southern coast of
The surface rupture associated with the 1944 Bolu-Gerede earthquake (Ms 7.3) is a 185 km-long str... more The surface rupture associated with the 1944 Bolu-Gerede earthquake (Ms 7.3) is a 185 km-long strand between the Lake Abant and town of Bayramoren at the western central part of the North Anatolian Fault. The rupture was subdivided into 5 main geometrical segments and a maximum right lateral displacement of 6 m was measured along the rupture zone during the MTA-GSJ joint study. The 1944 rupture includes the Ismetpasa segment, which is known to be since 1970. Average displacement of this segment is 3.0 m, including the 1951 earthquake, smaller then the western continuation of the rupture. We found triggered surface slip associated with the 17 August, 1999 Izmit earthquake (Mw 7.4) that is located 225 km from the epicenter of the mainshock, around the Ismetpasa section of the NAF in summer 2002. The evidence for the triggered slip was exhibited at three sites with 3--6 cm right lateral displacements along the 3 km-long strand of the fault, surroundings very near the Ismetpasa creep site. Those sites are: 1) Gas station on the Gerede-Cerkes state road, 2 km west of the creep site; we measured 3 cm displacement on a concrete garden wall of the station and a brick wall 100 m west of this. 2) Railway road, 200 m west of the creep site; a 6 cm right lateral displacement was found here. 3) At the village of Hamamli, 1 km east of the creeping, a 6 cm horizontal and 2 cm vertical offset were measured on the brick wall of house for livestock. All the owners explained that they noticed those cracks within several days after the Izmit earthquake. We also found new findings from the Ismetpasa creeping. A total displacement of 18--24 cm was measured on the Ismetpasa creep site by Ambraseys (1970) and Aytun (1995). We measured 40--41 cm of total displacement at the creep site including triggered slip by Izmit earthquake. The creep site and offset railway are located on the alluvial plain. However Site 1 of triggered slips is located on Eocene mudstone and alluvium, and at Site 3, the slip occured in alluvium that overlies an ophiolite wedge exposed along the fault zone around the Hamamli village. Following the mainshock, there are no recorded earthquakes associated with the surface slip in the region. For these reasons, we speculate that the triggered surface slips should be a superficial event along the fault. In addition, the Ismetpasa creeping might be related to superficial processes in a weak zone along the fault in the region, and it is triggered during the large earhquakes on the neighboring segments of the NAF.
Size and geometry of jogs among fault segments play important roles in rupture propagation during... more Size and geometry of jogs among fault segments play important roles in rupture propagation during large earthquakes. We carried out a very detail acoustic survey around the both ends of the Tepetarla (Sapanca) segment, which ruptured as the first sub-event of the 1999 Izmit earthquakes of Mw7.4, in the Izmit Bay and the Sapanca Lake, using a very high-resolution, acoustic profiling system ?Sono-prob?(SP-3W; 3-8kH) and a sidescan sonar (DF1000). Survey lines were designed at 250 m interval to capture the details of fault geometry. The Tepetarla segment on land is traceable for 19km almost straightly and continuously trending east to west with an average displacement of 2.8+-0.2 (one sigma) m. East of the segment continues in to the Sapanca Lake for about10km and makes a releasing double bends as the jog structure between Tepetarla and Arifiye segments. The double bends is 8 km-long and 2 km-wide consists of en-echelon faults with normal component of slip. East on the lake, the jog appeared on land for 2 km-long, as a 500 m-wide graben. Although South on the Arifiye segment there are several secondary faults making a hose tail structure, we couldn?t find any recent fault south of the tepetarla segment in the Sapanca Lake. West of the tepetarla segment continues into the Izmit Bay for 6 km making a releasing pull-apart structure between Golcuk and Tepetarla segments. The basin is 8 km-long, 3 km-wide and about 15 square km, surrounded by faults that have normal component. Subsidence of the large area of south coast of the Izmit Bay during the earthquake suggests that this pull-apart structure stretches at least several km deep. Those differentiations of geometry and size of jogs might strongly influence the rupture process of the 1999 Izmit earthquake.
ABSTRACT The Ismetpasa section of the central North Anatolian Fault Zone, which has ruptured duri... more ABSTRACT The Ismetpasa section of the central North Anatolian Fault Zone, which has ruptured during the 1944 Bolu-Gerede earthquake (Ms 7.3) and the 1951 Kursunlu earthquake (Ms 6.9) is known as creeping. We present new findings on the rate of stable creeping and triggered slip associated with the distant 1999 Izmit Earthquake. Across the eastern wall of a highway station at Ismetpasa (N 40§52'15'', E 32§37'30''), we measured 41cm of displacement using total station on 31st August 2002. In 1969, Ambrasys (1970) reported 24 cm displacement of the wall and Aytun(1995) measured 18cm. Between 1969 and 1972, Aytun(1995) also measured 0.6cm/yr average creeping rate using geodetic methods at the same site. Altay et al. (1991) observed 0.77cm/yr creeping rate using creep-meter between 1982 and 1990. These data provides us that cumulative displacement is 23cm and average creeping rate is approximately 0.7cm/yr between 1969 and 2002. In the early summer of 2002, we found the triggered surface slips of 3-6cm of right lateral probably associated with the 1999 Izmit earthquake of Ms7.4, at three sites along 3km-long strand of the Ismetpasa. The epicenter of the earthquake is located 225km, and the eastern tip of the surface rupture is 155km west of Ismetpasa. Those sites are 1) 2km west of the highway station, we observed 3cm displacement on the concrete garden wall of s gas station. The owner of the gas station explained that significant damage of the wall was realized right after the Izmit earthquake. 2) 200m west of the station we measured 6cm displacement on the railway road. 3) At Hamamli village, 1km east of the station, a few cm offset was founded on the brick-wall of house for livestock and on the paved road near the house a few days after the Izmit earthquake. We measured 6cm horizontal and 2cm vertical offset there. There is no information on a stable creeping at sites 1) and 2) since the 1999 earthquake. It is not clear whether creeping on the section has been constant or consisted of episodic small slips like the 1999 event since 1990. In addition such a high creeping rate can't be neglected when we consider the recurrence of large earthquake events on NAFZ. From these points of view, we started the periodic geodetic measurements of the fault creep at Ismetpasa.
The Gemlik Bay is located in the southeast part of Marmara Sea, where is one of the major active-... more The Gemlik Bay is located in the southeast part of Marmara Sea, where is one of the major active-faulting features seen in the NAF Zone. There are three sets of faults in and aroud the Gemlik Bay: 1) several south-dipping normal faults along southern coast of the Armtlu Peninsula 2) several continuous north-dipping normal faults along the southern coast of
The four segments of the northern strand of the North Anatolian Fault ruptured in the August 17, ... more The four segments of the northern strand of the North Anatolian Fault ruptured in the August 17, 1999 Izmit earthquake (Mw 7.4). The Arifiye segment is located central part of 1999 Izmit rupture, 30 km length, and maximum lateral displacement along the Izmit rupture was observed on this segment as 4.9 meters. The surface rupture has vertical component with maximum
The seismically active North Anatolian fault system (NAFS) is one of the most major intra-contine... more The seismically active North Anatolian fault system (NAFS) is one of the most major intra-continental transform faults in the world. The NAFS ruptured in a sequence of large earthquakes between 1939 and 1999, generally progressing from east to west. In general, multi-segment surface faulting developed associated with the earthquakes in this seqeuence. However, the 1942 earthquake (M 7.0) is located between the 1939 and 1943 multi-segment ruptures presents and likely to be a non-characteristic event in this 20th century sequence (Kondo and Emre, 2005). The 1942 event occurred on the Niksar-Erbaa fault and produced a 48 km-long surface rupture (Kondo and Emre, 2005). The surface rupture associated with the 1942 earthquake is divided into two main geometric sections by a restraining stepover. The 12 km-long restraining stepover is characterized with a push-up structure bounding by reverse faults. Probably, the 1942 event nucleated below this restraining stepover and propagated bilatera...
Repeatability of surface slip distribution through earthquake cycles is basis to evaluate size an... more Repeatability of surface slip distribution through earthquake cycles is basis to evaluate size and timing of future large earthquakes generated by active fault systems. In order to reveal surface slip history associated with paleoearthquakes on the North Anatolian fault system (NAFS), we have extensively performed 3D trenching survey on the 1942 Erbaa-Niksar earthquake (M 7.0) ruptures, to simultaneously reconstruct timing and surface slip associated with past large earthquakes. At Ayvaz site on the 1942 rupture, our 3D trench survey preliminary indicated that the penultimate earthquake, which can be correlated with the great Anatolian earthquake (M ~8.0) in 1668 AD, recorded larger surface slip of 6.0-8.0 m in comparison with the 1942 slip of 2.5 m. This result supports historical documents telling that the 1668 event ruptured for >600 km long on the central-eastern NAFS and it likely jumped across the 11-km-wide step-over that is the largest along the NAFS. In order to confirm ...
Kita ici bir transform fay olan Kuzey Anadolu Fayi (KAF), Marmara Bolgesi’nde Kuzey ve Guney olma... more Kita ici bir transform fay olan Kuzey Anadolu Fayi (KAF), Marmara Bolgesi’nde Kuzey ve Guney olmak uzere iki ana kola ayrilir. Bandirma ve Dokurcun Vadisi arasinda Guney kol saga sicramali sekmelerle birbirinden ayrilan, dogudan batiya dogru Geyve, Iznik ve Gemlik olmak uzere uc ana fay segmentinden olusur. Fay segmentlerinin uzunlugu 40 ile 57 km arasinda degisir. GPS verileri Guney kolda yaklasik 5 mm/yil kayma hizi onermektedir. 40 km uzunlugundaki Gemlik segmenti uzerinde gerceklestirdigimiz paleosismolojik kazilarda iki yuzey faylanmasi olayi gozlenmistir. Bunlar 1857 ve 1419 tarihsel depremleri ile denestirilebilmektedir. Gemlik fayindaki son iki deprem arasindaki tekrarlanma araligi 438 yildir. Bulgular, Iznik fayinda varligi bilinen 1419 depremindeki yuzey faylanmasina Gemlik fayinin da dahil oldugunu ve bu depremde en az 95 km uzunlugunda cok segmentli yuzey faylanmasi gelistigini gostermektedir. 5 mm/yillik kayma hizina gore KAF’nin Iznik Golu ile Dokurcun vadisi arasinda kalan kesiminde 595 yilda biriken yer degistirme miktari yaklasik 3 metre olarak hesaplanmaktadir. Buna gore Kuzey Anadolu Fayi’nin Guney kolunun da en az Kuzey kol kadar buyuk deprem ureteme potansiyeline sahip oldugu soylenebilir
TEZ1222Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 1992.Kaynakça (s. 95-98) var.ix, 100 ... more TEZ1222Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 1992.Kaynakça (s. 95-98) var.ix, 100 s. : rnk. res., hrt. ; 30 cm.…Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi Tarafından Desteklenmiştir
The Gemlik Bay is located in the southeast part of Marmara Sea, where is one of the major active-... more The Gemlik Bay is located in the southeast part of Marmara Sea, where is one of the major active-faulting features seen in the NAF Zone. There are three sets of faults in and aroud the Gemlik Bay: 1) several south-dipping normal faults along southern coast of the Armtlu Peninsula 2) several continuous north-dipping normal faults along the southern coast of
The surface rupture associated with the 1944 Bolu-Gerede earthquake (Ms 7.3) is a 185 km-long str... more The surface rupture associated with the 1944 Bolu-Gerede earthquake (Ms 7.3) is a 185 km-long strand between the Lake Abant and town of Bayramoren at the western central part of the North Anatolian Fault. The rupture was subdivided into 5 main geometrical segments and a maximum right lateral displacement of 6 m was measured along the rupture zone during the MTA-GSJ joint study. The 1944 rupture includes the Ismetpasa segment, which is known to be since 1970. Average displacement of this segment is 3.0 m, including the 1951 earthquake, smaller then the western continuation of the rupture. We found triggered surface slip associated with the 17 August, 1999 Izmit earthquake (Mw 7.4) that is located 225 km from the epicenter of the mainshock, around the Ismetpasa section of the NAF in summer 2002. The evidence for the triggered slip was exhibited at three sites with 3--6 cm right lateral displacements along the 3 km-long strand of the fault, surroundings very near the Ismetpasa creep site. Those sites are: 1) Gas station on the Gerede-Cerkes state road, 2 km west of the creep site; we measured 3 cm displacement on a concrete garden wall of the station and a brick wall 100 m west of this. 2) Railway road, 200 m west of the creep site; a 6 cm right lateral displacement was found here. 3) At the village of Hamamli, 1 km east of the creeping, a 6 cm horizontal and 2 cm vertical offset were measured on the brick wall of house for livestock. All the owners explained that they noticed those cracks within several days after the Izmit earthquake. We also found new findings from the Ismetpasa creeping. A total displacement of 18--24 cm was measured on the Ismetpasa creep site by Ambraseys (1970) and Aytun (1995). We measured 40--41 cm of total displacement at the creep site including triggered slip by Izmit earthquake. The creep site and offset railway are located on the alluvial plain. However Site 1 of triggered slips is located on Eocene mudstone and alluvium, and at Site 3, the slip occured in alluvium that overlies an ophiolite wedge exposed along the fault zone around the Hamamli village. Following the mainshock, there are no recorded earthquakes associated with the surface slip in the region. For these reasons, we speculate that the triggered surface slips should be a superficial event along the fault. In addition, the Ismetpasa creeping might be related to superficial processes in a weak zone along the fault in the region, and it is triggered during the large earhquakes on the neighboring segments of the NAF.
Size and geometry of jogs among fault segments play important roles in rupture propagation during... more Size and geometry of jogs among fault segments play important roles in rupture propagation during large earthquakes. We carried out a very detail acoustic survey around the both ends of the Tepetarla (Sapanca) segment, which ruptured as the first sub-event of the 1999 Izmit earthquakes of Mw7.4, in the Izmit Bay and the Sapanca Lake, using a very high-resolution, acoustic profiling system ?Sono-prob?(SP-3W; 3-8kH) and a sidescan sonar (DF1000). Survey lines were designed at 250 m interval to capture the details of fault geometry. The Tepetarla segment on land is traceable for 19km almost straightly and continuously trending east to west with an average displacement of 2.8+-0.2 (one sigma) m. East of the segment continues in to the Sapanca Lake for about10km and makes a releasing double bends as the jog structure between Tepetarla and Arifiye segments. The double bends is 8 km-long and 2 km-wide consists of en-echelon faults with normal component of slip. East on the lake, the jog appeared on land for 2 km-long, as a 500 m-wide graben. Although South on the Arifiye segment there are several secondary faults making a hose tail structure, we couldn?t find any recent fault south of the tepetarla segment in the Sapanca Lake. West of the tepetarla segment continues into the Izmit Bay for 6 km making a releasing pull-apart structure between Golcuk and Tepetarla segments. The basin is 8 km-long, 3 km-wide and about 15 square km, surrounded by faults that have normal component. Subsidence of the large area of south coast of the Izmit Bay during the earthquake suggests that this pull-apart structure stretches at least several km deep. Those differentiations of geometry and size of jogs might strongly influence the rupture process of the 1999 Izmit earthquake.
ABSTRACT The Ismetpasa section of the central North Anatolian Fault Zone, which has ruptured duri... more ABSTRACT The Ismetpasa section of the central North Anatolian Fault Zone, which has ruptured during the 1944 Bolu-Gerede earthquake (Ms 7.3) and the 1951 Kursunlu earthquake (Ms 6.9) is known as creeping. We present new findings on the rate of stable creeping and triggered slip associated with the distant 1999 Izmit Earthquake. Across the eastern wall of a highway station at Ismetpasa (N 40§52'15'', E 32§37'30''), we measured 41cm of displacement using total station on 31st August 2002. In 1969, Ambrasys (1970) reported 24 cm displacement of the wall and Aytun(1995) measured 18cm. Between 1969 and 1972, Aytun(1995) also measured 0.6cm/yr average creeping rate using geodetic methods at the same site. Altay et al. (1991) observed 0.77cm/yr creeping rate using creep-meter between 1982 and 1990. These data provides us that cumulative displacement is 23cm and average creeping rate is approximately 0.7cm/yr between 1969 and 2002. In the early summer of 2002, we found the triggered surface slips of 3-6cm of right lateral probably associated with the 1999 Izmit earthquake of Ms7.4, at three sites along 3km-long strand of the Ismetpasa. The epicenter of the earthquake is located 225km, and the eastern tip of the surface rupture is 155km west of Ismetpasa. Those sites are 1) 2km west of the highway station, we observed 3cm displacement on the concrete garden wall of s gas station. The owner of the gas station explained that significant damage of the wall was realized right after the Izmit earthquake. 2) 200m west of the station we measured 6cm displacement on the railway road. 3) At Hamamli village, 1km east of the station, a few cm offset was founded on the brick-wall of house for livestock and on the paved road near the house a few days after the Izmit earthquake. We measured 6cm horizontal and 2cm vertical offset there. There is no information on a stable creeping at sites 1) and 2) since the 1999 earthquake. It is not clear whether creeping on the section has been constant or consisted of episodic small slips like the 1999 event since 1990. In addition such a high creeping rate can't be neglected when we consider the recurrence of large earthquake events on NAFZ. From these points of view, we started the periodic geodetic measurements of the fault creep at Ismetpasa.
The Gemlik Bay is located in the southeast part of Marmara Sea, where is one of the major active-... more The Gemlik Bay is located in the southeast part of Marmara Sea, where is one of the major active-faulting features seen in the NAF Zone. There are three sets of faults in and aroud the Gemlik Bay: 1) several south-dipping normal faults along southern coast of the Armtlu Peninsula 2) several continuous north-dipping normal faults along the southern coast of
The four segments of the northern strand of the North Anatolian Fault ruptured in the August 17, ... more The four segments of the northern strand of the North Anatolian Fault ruptured in the August 17, 1999 Izmit earthquake (Mw 7.4). The Arifiye segment is located central part of 1999 Izmit rupture, 30 km length, and maximum lateral displacement along the Izmit rupture was observed on this segment as 4.9 meters. The surface rupture has vertical component with maximum
The seismically active North Anatolian fault system (NAFS) is one of the most major intra-contine... more The seismically active North Anatolian fault system (NAFS) is one of the most major intra-continental transform faults in the world. The NAFS ruptured in a sequence of large earthquakes between 1939 and 1999, generally progressing from east to west. In general, multi-segment surface faulting developed associated with the earthquakes in this seqeuence. However, the 1942 earthquake (M 7.0) is located between the 1939 and 1943 multi-segment ruptures presents and likely to be a non-characteristic event in this 20th century sequence (Kondo and Emre, 2005). The 1942 event occurred on the Niksar-Erbaa fault and produced a 48 km-long surface rupture (Kondo and Emre, 2005). The surface rupture associated with the 1942 earthquake is divided into two main geometric sections by a restraining stepover. The 12 km-long restraining stepover is characterized with a push-up structure bounding by reverse faults. Probably, the 1942 event nucleated below this restraining stepover and propagated bilatera...
Repeatability of surface slip distribution through earthquake cycles is basis to evaluate size an... more Repeatability of surface slip distribution through earthquake cycles is basis to evaluate size and timing of future large earthquakes generated by active fault systems. In order to reveal surface slip history associated with paleoearthquakes on the North Anatolian fault system (NAFS), we have extensively performed 3D trenching survey on the 1942 Erbaa-Niksar earthquake (M 7.0) ruptures, to simultaneously reconstruct timing and surface slip associated with past large earthquakes. At Ayvaz site on the 1942 rupture, our 3D trench survey preliminary indicated that the penultimate earthquake, which can be correlated with the great Anatolian earthquake (M ~8.0) in 1668 AD, recorded larger surface slip of 6.0-8.0 m in comparison with the 1942 slip of 2.5 m. This result supports historical documents telling that the 1668 event ruptured for >600 km long on the central-eastern NAFS and it likely jumped across the 11-km-wide step-over that is the largest along the NAFS. In order to confirm ...
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