The SeisComP3 (SC3) real-time software is widely used in the seismological community. It provides automatic hypocenter and magnitude solutions, but with limited manual processing capabilities. The SEISAN software is also well known and provides a large number of facilities with manual processing and a simple database for storage. SEISAN and SC3 share data structure for continuous waveform data but not for parameter data. The software presented here, SC2SEI, enables a simple, manual or automatic, transfer of SC3 detected events to SEISAN. Comparing the hypocenters and magnitudes, as calculated with the same data on both systems, gives nearly identical results, indicating that processing on either system is equally valid. Thus, combining SC3 and SEISAN makes it possible to get the best out of both systems.

Both the geometry and the depth of the seismogenic zone of the North Anatolian Fault under the Marmara Sea (the Main Marmara Fault (MMF)) are poorly understood, in part because of the fault's undersea location. We recorded 10months of microseismic data with a dense array of ocean bottom seismographs and then applied double-difference relocation and 3-D tomographic modeling to obtain precise hypocenters on the MMF beneath the central and western Marmara Sea. The hypocenters show distinct lateral changes along the MMF: (1) both the upper and lower crust beneath the Western High are seismically active and the maximum focal depth reaches 26km; (2) seismic events are confined to the upper crust beneath the region extending from the eastern part of the Central Basin to the Kumburgaz Basin; and (3) the magnitude and direction of dip of the main fault change under the Central Basin, where there is also an abrupt change in the depth of the lower limit of the seismogenic zone. We attribute this change to a segment boundary of the MMF. Our data show that the upper limit of the seismogenic zone corresponds to sedimentary basement. We also identified several seismically inactive regions within the upper crust along the MMF; their spatial extent beneath the Kumburgaz Basin is greater than beneath the Western High. From the comparison with seafloor extensometer data, we consider that these regions might indicate zones of strong coupling that are accumulating stress for release during future large earthquakes.

Earthquake Early Warning (EEW) is provided to public users nationwide in Japan from October 2007. The attention to the system has been increasing by broadcasting from the television, radio, and mobile phone. The contribution of the automatic processing technology of observing waveform data is very important for the development of EEW. In this session, we will discuss on the technical improvement of EEW, the practical application of EEW, and the automatic processing technology.

The western escarpment of the Sea of Marmara has recently been recognized as the site of intensive gas emissions escaping from the seafloor. Visual observations with the Nautile submersible indicate that gas escapes from elongated tensile cracks oriented to the northwest in the direction of the maximum principal stress. Here, we report results from a 25-day test in 2007 with four ocean-bottom seismometers (OBSs) showing that this area is also characterized by microseismic activity. A cluster of 13 small-magnitude earthquakes aligned northwest occurred in less than 30 hr at shallow crustal depth below the western slope of the Tekirdag basin. The only two focal mechanisms resolvable using land and sea-bottom data reveal normal faulting with strike-slip components, consistent with the stress field expected in this area. It is suggested that tectonic strain below the western slope of the Tekirdag basin contributes to maintaining a high permeability in fault zones and that the fault network provides conduits for deep-seated fluids to rise up to the seafloor.