We present the up-to-date seismicity associated with the main fault system in the Marmara Sea as a series of space-time sections. The aim is to reveal the hidden orders and to facilitate prompt interpretation. The earthquake data is obtained from the KOERI-RETMC database every minute. With new earthquakes the figures and maps are updated immediately; otherwise, they are regenerated every hour. The following points should be considered regarding the images.
- There are 8 figures showing time-space sections of seismicity for different periods. Earthquakes are projected on the line segments that represent the Main Marmara fault.
- The yellow line segments, ‘W-E’, on the maps show the section. Earthquakes within a 20 km range are projected in the section.
- For each figure X, there are 3 associated illustrations with a corresponding period. Xa shows the seismicity for the whole region, while Xb displays the events in the window around the section. Figure Xc shows the depth distribution of events along the section. Their links are given below each figure.
- Although cluttering the maps and figures, to emphasize the probable rupture initiation depth for major earthquakes, the fault lines are colored according to depth, 17 km, of the 17 August 1999 (Mw 7.6) Izmit earthquake.
- The thick green line along the left axis of each figure is the projection of the Main Marmara fault systems (Le Pichon et al., 2001).
- The thick green line in figures 6, 7 and 8 that corresponds with 1999 is the projection of the surface rupture of the 1999 Izmit earthquake (Hartleb et al., 2002; Langridge et al., 2002). The surface rupture is also shown on all maps similarly.
- The thick red line segments, labeled A, B, C and D, on the maps and also along the right axis of each figure represent barriers. Most likely these silent fault segments will release the main seismic energy during their rupture.
- Barrier A corresponds with the uncertain segment (dotted green) of the 1999 Izmit rupture (Hartleb et al., 2002; Langridge et al., 2002).
The earthquake data for this project is downloaded from the website of the “Regional Earthquake-Tsunami Monitoring Center” (RETMC) of the Kandilli Observatory and Earthquake Research Institute. We appreciate the release of their products to the public. The figures are produced by using the “Generic Mapping Tool” (GMT) and we thank the developers of the software (Wessel et al., 2013).
- Hartleb RD, Dolan JF, Akyuz HS, et al. Surface rupture and slip distribution along the Karadere segment of the 17 August 1999 Izmit and the western section of the 12 November 1999 Duzce, Turkey, earthquakes. Bulletin of the Seismological Society of America. 2002;92:67–78.
- Langridge R, Stenner HD, Fumal T, et al. Geometry, slip distribution, and kinematics of surface rupture on the Sakarya fault segment during the 17 August 1999 Izmit, Turkey, earthquake. Bulletin of the Seismological Society of America. 2002;92:107–125.
- Le Pichon X, Şengör A, Demirbağ E, et al. The active main Marmara fault. Earth and Planetary Science Letters. 2001;192:595–616.
- Wessel P, Smith WH, Scharroo R, Luis J, Wobbe F. Generic mapping tools: improved version released. Eos, Transactions American Geophysical Union. 2013;94:409–410.