Heat flow in the Sea of Marmara Central Basin: Possible implications for the tectonic evolution of the North Anatolian fault

Geology ◽  
2011 ◽  
Vol 40 (1) ◽  
pp. 3-6 ◽  
Author(s):  
C. Grall ◽  
P. Henry ◽  
D. Tezcan ◽  
B. Mercier de Lepinay ◽  
A. Becel ◽  
...  
Keyword(s):  
Heat Flow ◽  
Tectonic Evolution ◽  
North Anatolian Fault ◽  
Central Basin ◽  
Sea Of Marmara ◽  
The North

scholarly journals Estimation of successive co-seismic vertical offsets using coeval sedimentary events – application to the Sea of Marmara's Central Basin (North Anatolian Fault)

2014 ◽  
Vol 2 (6) ◽  
pp. 4069-4100
Author(s):  
C. Beck ◽  
C. Campos ◽  
K. Eriş ◽  
N. Çağatay ◽  
B. Mercier de Lepinay ◽  
...  
Keyword(s):  
Seismic Activity ◽  
Major Part ◽  
Vertical Component ◽  
North Anatolian Fault ◽  
Central Basin ◽  
Deep Part ◽  
Sea Of Marmara ◽  
Direct Estimation ◽  
The North ◽  
Depositional Process

Abstract. In the deep part of the Sea of Marmara (Turkey), the sedimentation developing upon the North Anatolian Fault is strongly influenced by the associated seismic activity. Specific layers (homogenites-turbidites), representing individual sedimentary events, have been characterized along three giant piston cores retrieved from Çinarcik and Central (or Orta) basins. Analyzed sediments represent the last 12 to 17 kyr BP. For a 2 kyr-lasting interval, 11 events could be precisely correlated on both sides of the Central Basin's southern scarp. For each of them, based on the specific depositional process, the thickness difference between the two sites was considered as a direct estimation of the vertical component of a coeval co-seismic offset. The homogenite (upper) term accounts for the major part of the thickness difference. The 6 most significant values range from 36 cm to 144 cm and are likely representing dominantly normal throws, with estimated paleomagnitudes (Mw) ranging from 5.9 to 6.6.

scholarly journals Contrasting seismogenic behaviors on the North Anatolian Fault in the Sea of Marmara

2020 ◽  
Author(s):  
Pierre Henry ◽  
Céline Grall ◽  
M Sinan Özeren ◽  
Volkan Özbey ◽  
Gülsen Uçarkus ◽  
...  
Keyword(s):  
Heat Flow ◽  
Sedimentary Cover ◽  
Large Earthquake ◽  
Fault Slip ◽  
North Anatolian Fault ◽  
Fault System ◽  
Seismogenic Zone ◽  
Sea Of Marmara ◽  
The North

<p>Since the 1999 Izmit-Kocaeli earthquake, the Main Marmara Fault (MMF) of the North Anatolian Fault system in the Sea of Marmara has been considered at an imminent risk for a large earthquake. Land geodesy has difficulties characterizing the distribution of interseismic loading, and hence of slip deficit, on the offshore faults, and notably on the Istanbul-Silivri segment of the NAF. The need to clarify the status of offshore fault segments has motivated seafloor monitoring experiments and marine geophysical and sedimentological studies, notably in the framework of EMSO consortium and MARSITE and MAREGAMI projects. Results from cross-disciplinary projects have shown that aseismic creep, spatially correlated to active gas venting at the seafloor, occurs on the Western segment of the MMF. This segment is also capable to large earthquake ruptures such as the 1912 event. On the eastern part of the Sea of Marmara, the Istanbul-Silivri and Prince Island segments appear essentially locked. Moreover, the base of the seismogenic zone and locking depth appears to shallow (from 15-20 to 10-15 km) from west to east.</p><p>On one hand, we propose to further evaluate fault slip rates and distribution of locking ratio on individual fault segments using an elastic block model constrained by land geodesy data and marine observations (long-term fault slip rate estimates, local acoustic ranging results). On the other hand, we evaluate the temperature at the seismogenic depths by basin modelling. Results suggest that spatial variations of fault behavior in the Sea of Marmara may result from a combination of factors. First, thermogenic gas generation within the > 6 km thick sedimentary cover in the Western Sea of Marmara may contribute to unlock the shallow part of the fault by generating overpressures. Second, heterogeneity of the crust composition could be a factor as the North Anatolian Fault system follows the intra-pontide ophiolitic suture. For instance, long term post-seismic creep onland at Ismet Paşa has been related to the presence of serpentinite in the fault zone. Moreover, high-density magnetic bodies have been identified along the MMF. Third, varying thermal regimes between the Western and Eastern parts of the Sea of Marmara may account for variations in the seismogenic depths. Seafloor heat flow in the Sea of Marmara is strongly affected by sediment blanketing and basin modeling considering this process suggests that the crustal heat flow is about 20 mW/m<sup>2</sup> higher in the eastern part than in western part of the Sea of Marmara. This difference may be explained by a more spread out crustal extension in the western Sea of Marmara.</p>

scholarly journals Estimation of successive coseismic vertical offsets using coeval sedimentary events – application to the southwestern limit of the Sea of Marmara's Central Basin (North Anatolian Fault)

2015 ◽  
Vol 15 (2) ◽  
pp. 247-259 ◽  
Author(s):  
C. Beck ◽  
C. Campos ◽  
K. K. Eriş ◽  
N. Çağatay ◽  
B. Mercier de Lepinay ◽  
...  
Keyword(s):  
Major Part ◽  
Vertical Component ◽  
North Anatolian Fault ◽  
Central Basin ◽  
Local Behavior ◽  
Before Present ◽  
Sea Of Marmara ◽  
The North ◽  
Depositional Process ◽  
Coseismic Offset

Abstract. In the deep part of the Sea of Marmara (Turkey), the sedimentation developing upon the North Anatolian Fault is strongly influenced by the associated seismic activity, through gravity reworking (fluidized landslides) and tsunamis. Specific layers (homogenites + turbidites, HmTu), representing individual sedimentary events, have been characterized along three giant piston cores retrieved from the Çinarcik and Central (or Orta) basins. Pre-Holocene, nonmarine sediments, were analyzed, representing the last 12–17 kyr BP (before present). For a 2 kyr long interval, 11 events could be precisely correlated on both sides of the Central Basin's southwestern scarp. For each of them, based on the specific depositional process, the thickness difference between the two sites was considered as a direct estimation of the vertical component of a coeval coseismic offset. The homogenite (upper) component accounts for the major part of the thickness difference (ranging from 36 to 144 cm). These offsets were considered as likely representing dominantly vertical throws, along the transtensional southwestern boundary of the inner, pull-apart Central Basin. In terms of natural hazards, further investigations on this local behavior should rather be directed to tsunami genesis.

scholarly journals The North Anatolian fault in the Sea of Marmara

2003 ◽  
Vol 108 (B4) ◽  
Author(s):  
X. Le Pichon ◽  
N. Chamot-Rooke ◽  
C. Rangin ◽  
A. M. C. Sengör
Keyword(s):  
North Anatolian Fault ◽  
Sea Of Marmara ◽  
The North

Locking Behavior of Main Marmara Fault in Western Turkey During Interseismic Period

2020 ◽  
Author(s):  
Zeynep Yılmaz ◽  
Ali Özgün Konca ◽  
Semih Ergintav
Keyword(s):  
3D Structure ◽  
Slip Rate ◽  
Fault Slip ◽  
North Anatolian Fault ◽  
Gps Data ◽  
Strain Accumulation ◽  
Sea Of Marmara ◽  
Western Turkey ◽  
The North ◽  
Fault Slip Rate

<p>The North Anatolian Fault (NAF) produced multiple earthquakes of M>7 throughout the 20th century, while the part of NAF beneath Sea of Marmara did not rupture during this period. Analysis of the Main Marmara Fault's interseismic behavior, the most active branch of the North Anatolian Fault in this region, in terms of locking depth and fault slip rate is critical for evaluating the region's seismic risk with a population of more than 20 million, as it provides information about the seismic moment deficit that may release in a potential future earthquake.</p><p>In this study, we modeled the Main Marmara Fault's interseismic locking with realistic geometry and 3D structure including sedimentary basins, by implementing a 3D finite element approach and using interseismic GPS velocities. We have optimized the fits with GPS data by evaluating cases where each fault segment is constrained by a fault slip rate below a predefined locking depth ranging from 0 to 20 km. Preliminary models reveal that a difference in locking depth is required between the Western Marmara and the eastern end of the Ganos Segment entering the Sea of Marmara. This result, which is consistent with seismicity studies and other previous studies using 1D profiles shows that the strain accumulation under Western Marmara is less and that the locking depths or couplings are not similar in these two segments. For the Princes' Islands Segment, further analysis is required due to complexity in the GPS data. Recent earthquakes along Silivri also indicate that the strain accumulation is complex with most mechanisms showing significant thrust component. We have also calculated various possible strain accumulation patterns and compared the strain rate field around the Main Marmara Fault. Our results show that in most cases the change in the seismicity of each segment is consistent with the interseismic behavior associated with its fault locking.</p><p>(This research has been supported by Boğaziçi University Scientific Research Projects Coordination Unit. Project Number: 15022, 2019)</p>

The effects of the North Anatolian Fault Zone on the latest connection between Black Sea and Sea of Marmara

2002 ◽  
Vol 190 (1-2) ◽  
pp. 367-382 ◽  
Author(s):  
Fazlı Y Oktay ◽  
Erkan Gökaşan ◽  
Mehmet Sakınç ◽  
Cenk Yaltırak ◽  
Caner İmren ◽  
...  
Keyword(s):  
Fault Zone ◽  
Black Sea ◽  
North Anatolian Fault ◽  
Sea Of Marmara ◽  
North Anatolian Fault Zone ◽  
The North
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