23.11.2022 tarihli Mw=5.9 Düzce depreminin kuvvetli yer hareketi verileri ile analizi ve bölgenin tektonik yapısı
Analysis of the Mw = 5.9 Düzce earthquake with strong ground movement data and the tectonic structure of the region form 23.11.2022
Yazar: MURAT ORHUN ÇELİK
Danışman: DR. ÖĞR. ÜYESİ GÜNAY BEYHAN
Sakarya Üniversitesi / Fen Bilimleri Enstitüsü / Jeofizik Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2023
Konu: Jeofizik Mühendisliği = Geophysics Engineering

Özet:
Düzce, Türkiye'nin Batı Karadenizinde yer alan ilimizdir. Kuzey Anadolu Fay Hattının (KAFH) etkisindendir. Uluslararası merkezlerin sismoloji verilerine göre, 23 Kasım 2022 tarihinde, Türkiye saati ile 04.08'de, merkezi Düzce ili, Gölyaka ilçesinin 6 km kuzeydoğusu olan büyüklüğü Mw 5,9 ve 6-19 km odak derinliğine sahip sığ odaklı bir deprem oluşmuştur. 
Deprem sonrası saat 09.05 anına kadar; Büyüklüğü en fazla 4.3 olan 220 artçı şok değeri kaydedilmiştir. Deprem; Düzce İli, olmak üzere Ankara, İstanbul, Kocaeli, Bolu, Sakarya, Kütahya, Bilecik, Bursa, Eskişehir ve çevredeki birçok il ve ilçede hissedilmiştir.
Ölçülmüş en büyük ivme değeri Düzce Merkez istasyonu D-B yönü 593,56 cm/sn2, KG bileşeninde ise 590.42 cm/sn2 değeri kaydedilmiş olup; Bu istasyonlarda ölçülen ivme değerleri 100 gal'ın üzerinde bulunan 5 istasyonun ivme verileri bu çalışma kapsamında değerlendirilmiştir. Deprem merkez üssü noktasına en yakın mesafede Düzce-Gölyaka istasyonunun dalga formuna bakıldığında, DB bileşen değerinin KG bileşeninden daha büyük olduğu görülmüştür. Yakındaki istasyonlar da fayda oluşan kırılma yönünün yayılması, istasyona doğru olup, faya dik bulunan bileşende uzun periyotlu enerji birikimine yol açabilir. Bu noktada paralel bileşende ki dalganın genliği büyük olduğu için depremin süresi daha kısa olarak kaydedilmektedir. KG bileşeninin ivme kayıtlarının büyük genlikli olması durumunda, depremin yüksek frekansı kısa etkili süresi dikkate alındığında, ileriye doğru (forward directivity) bir etkiden söz edilebileceği varsayılabilir.
Deprem kayıt verilerinin işlenmesinde, ana şoku zaman alanında kaydetmek için eksen kayması düzeltme işlemi (baseline-offsets-correction) ve 0.2 ile 25 Hz aralığında değişen bir Butterworth band geçişli filtre uygulandı. Bu dönüştürülmüş hız ve yer değiştirme dalga formlarını üretmiştir. 
Çalışmamıza konu Depremin kaynak (odak) mekanizması çözümüne göre fay hareketinin sağ yönlü ve doğrultu atımlı olduğu anlaşılmaktadır.

Abstract:
Düzce is our province located in the Western Black Sea of Turkey.  It is the influence of the North Anatolian fault Line (KAFH).  According to the seismology data of the international centers, on November 23, 2022, at 04.08, Turkey time, a shallow-focused earthquake occurred with a focal depth of MW 5.9 and 6-19 km, with a focal depth of 6 km northeast of the central Düzce province, Golyaka district. 
After the earthquake until 09.05:00;  220 aftershock values with a maximum size of 4.3 were recorded.  Earthquake;  And Anchorage. It was felt in Sakarya, Kütahya, Bilecik, Bursa, Eskişehir and many provinces and districts around it. 
When we look at the relationship of the fault affecting the formation of the earthquake and the relationship of the damage to the geological structure, the main and aftershocks where the damage intensified occurred in the sector between Düzce and Golyaka.  As a result of possible studies, no surface fracture related to the fault affecting the quake was observed.  At this point, especially in the area where the Karadere segment cut the Great Melen Tea, surface deformations of earthquake origin of the type of advanced lateral spread on flood plain sediments were observed. 
The largest measured acceleration value is 593.56 cm/s2 in the Düzce Central Station D-B direction and 590.42 cm/s2 in the QA component;  The acceleration data of 5 stations whose acceleration values measured at these stations are above 100 gal were evaluated within the scope of this study. Looking at the wave form of the Düzce-Golyaka station at the closest distance to the earthquake EPICENTER point, it was seen that the component value of  DB was greater than the component of KG.  In nearby stations, the diffusion of the benefit direction towards the station can lead to long-term energy accumulation in the component perpendicular to the fault.  The length of time of the earthquake is shorter because the amplitude of the wave in the parallel component is greater.  If the acceleration records of the QA component are large amplitude, it can be assumed that a forward directivity effect can be mentioned, given the short duration of the earthquake's high frequency. 
In the processing of earthquake log data, a baseline-offset-correction process was applied to record the main shock in the time space, and a Butterworth band-pass filter ranging from 0.2 to 25 Hz was applied.  It produced these converted velocity and displacement waveforms. 
As seen in the Düzce-Golyaka station speed diagram, the greatest speed amplitude of each component is Vmax = 30.66 cm/s in the KG direction, Vmax = 16.80 cm/s in the DB direction and Vmax = 7.11 cm/s in the vertical direction.  Displacements are the largest values of displacements in the QA, DB and Vertical directions when viewed in the waveform;  10.90 cm, 4.29 cm and 2.34 cm are determined. 
The Akyazı section is observed in pre-quaternary basic rocks. During the 17 August and 12 November earthquakes, activity on the Dzuce fault system was observed. The earthquake that occurred on August 17 (M = 7.4) developed 130 km. The eastern part of the surface crack of 30 km in length is located in the Düzce fault line.  It is known
to be the East-Southwest stretch fault between Sapanca Lake-Cumayeri-Trench on the west side of Düzce Basin.  The length of this right-directional pulsing fault is 50 km. 
The fault mapped on the Adazazarı plain shows morphologically in the 25 km section between Çammayeri and Hendek.  The Plio-Quaternary old Karapurcek formation, its morphology is interrupted by the fault of this zone, which consists of right lateral movements and wide pressure ridges, and the fault forms the dove between this formation and the mainland and is basically located. 
The 1994 Düzce-Trench earthquake (M = 6.5) probably occurred on the mentioned fault.  In the northwest of the ditch, surface cracks have been observed in recent earthquakes.  This is the right-hand path.  Shape changes in small sizes during fracture, 2-5 cm in the range, the right direction progress is achieved. 
In the historical period (1800 BC – 1900 AD), the Northern and Southern branches of the Northern Anatolian fault Line area followed by 358 and 715 earthquakes with a violent value of Io = IX were experienced in the region.  In addition, many earthquakes with a magnitude of Io = VIII occurred on the North Anatolian Line area in the southeast and west of Düzce. 
The rapid fault levels separation made by our center indicates that the earthquake occurred on a downward pulsed fault. 
The most precise measure against earthquakes is that the people living in the region should live in earthquake-resistant structures and the houses they buy should be earthquake-resistant.
The source (focus) mechanism solution of the earthquake shows that there is a fault movement with a right-hand and directional pulses (Şekil 3.1).
Historical and instrumental earthquakes, it is seen that a large number of destructive earthquakes have occurred in the region and that these earthquakes have caused a large number of lives and property loss.  The seismicity of the region is determined by the North Anatolian fault Zone.  Different researchers measured the surface fracture length of the Düzce earthquake and the highest right lateral displacement.  The length of the surface fracture is between 30 – 45 km, and the right lateral displacement is between 380 – 490 cm. 
This earthquake, which occurred in Düzce on November 23, 2022 and whose magnitude is MI=5.9, contains very important parameters for seismological studies.  The right lateral direction with KD-GB direction is caused by a pulsed fault.  According to the AFAD data, the greatest acceleration value of the earthquake was measured as 8105-coded gal, one of the 5 accelerometers closest to the earthquake zone.  In this earthquake, which occurred at an average depth of 10 km, the acceleration of 593.56 in the East-West component, measured from the largest horizontal earth-level Central accelerometer station, was generally below the expected empirical value. The most damage during the earthquake occurred in Düzce provincial center, Golyaka, Cumayeri and Gümüşova district centers, Saridere, Yeşilova, Icmeler, Kemeryani, Koprubaşı and Yayakbaşı villages.  Structural damage has generally been observed in buildings built with a traditional building style of stone or a creepy type on the ground that is geologically suitable for ground augmentation. 
One of the most critical factors in the formation of structural damage in an earthquake is the frequency content of the earthquake.  The frequency values measured at the stations where high amplitude acceleration values of 4.6 Hz to 11.4 Hz are recorded and calculated in this earthquake show the basic characteristics of this magnitude and the fault structure.  In this context, according to the results of Fourier analysis applied to the data of the stations whose records were evaluated; 8105 0.17 s at QA component at Düzce Central Station. 0.21 sec on DB component. And 0.08 sec on the vertical component. Waves with wavelength were effective. 8106 0.54 s at QA component at Düzce Center 2 station. 0.46 sec on DB component. And 1.63 sec on the vertical component. Waves with wavelength were effective. 8109 1.42 s in QA component at Düzce Golyaka Station. 1.23 sec on DB component. And 1.65 sec on the vertical component. Waves with wavelength were effective. 8110 Düzce Akçakoca station 0.25 sec in KG component. 0.22 sec on DB component. And 0.09 sec on the vertical component. And the jokes are impactful.  0.18 s in the KG component of the 5414 Sakarya Karasu station located at the most distant distance from the earthquake. 0.28 sec on DB component. And 0.22 sec on the vertical component. And the jokes are impactful. 
It is known that if the period of the floor and the structure are of the same value, resonance will occur and therefore damage the structure.  Similarly, if we take the values of the building vibration period for both the Düzce and the earthquake-affected region as an average of 0.1 sec per floor, the vibration period values of all the above stations are seen to be in the range of 0.08 s to 1.65 s.