MATERIALS AND METHODS

The research cruise was carried out with the 61 meter R/V Urania (Fig.8), owned and operated by SO.PRO.MAR. and on long-term lease to CNR. The ship is normally used for geological, geophysical and oceanographical work in the Mediterranean Sea and adjoining waters, including but not limited to, the Atlantic Ocean, the Red Sea, and the Black Sea.

R/V Urania is equipped with DGPS and SEAPATH positioning system (satellite link by FUGRO), single-beam and multibeam bathymetry and integrated geophysical and oceanographical data acquisition systems, including ADCP, CHIRP SBP and other Sonar Equipment, other than water and sediment sampling. Additional equipment can be accommodated on the keel or towed.

**Figure 8:** *R/V Urania*.
$\begin{figure}\centerline{\epsfig{file=IMG/urania_sinistra.eps,width=12.5cm}} \end{figure}$

NAVIGATION AND DATA ACQUISITION

The vessel was set-up for data acquisition and navigation with PDS-2000 software by RESON, interfacing by a multiserial and Ethernet link several instruments, among them the DGPS (Fugro), the Atlas-Krupp Deso-25 single-beam echosunder, the MAHRS MRU and the meteorological station. The position and depth data were also distributed to the CTD data acquisition console. A Kongsberg processor running the SIS software, collected the multibeam data, including a SEAPATH MRU, compass, and DGPS. The MBES was the 70kHz, 400 1x2°, 150°aperture EM-710 (2000 m range) model by Kongsberg, with sonar head positioned on the ship's keel using a V-shaped steel frame. A Sound Velocity probe at the keel 1m above the Sonar Head is interfaced directly to the MBES processor, thus providing the necessary real-time data for the beam-forming. CTD casts were used for input of the sound velocity profile to the system. An Anderaa Meteorological Station was also made available, at a rate of one measurement every 5 minutes.

CTD DATA

CTD casts were taken throughout the surveyed areas, for sound velocity analysis, and were used for real-time MBES acquisition and post-processing. On the way from and to Italy, several Deep Blue XBT launches data were collected by a Sippican Mod. MK21 profiler.

The position of the XBT and CTD stations are reported in Table 3 and can be viewed in Fig.3 and Fig.4, respectively.

CHIRP SBP

SBP data was acquired by the 16 transducers, hull mounted BENTHOS (DATASONICS) Mod.CAP-6600 CHIRP-II profiler, with operating frequencies ranging between 2 and 7 kHz. The pulse length was mantained at 20 ms while the trigger rates varied from 0.25 to 1 seconds according to water depth. Digital data acquired by the Communication Technology SWANPRO software were recorded in the XTF format on local disks and transferred on the network upon request. Backups were loaded on HD and DVD. The navigation data was made available to the system as lat/long by NMEA sentences of the DGPS receiver at a rate of aproximately 1 Hz or by the PDS200's NMEA at 1Hz. The XTF data were then converted to SEG-Y by the Triton-Elics's Xtf2Seg software. This latter data were then input to the ISMAR's SEISPRO software [Gasperini and Stanghellini(2009)] for data processing and display. Since the SEG-Y converted positions were found to be truncated, the accurate position data were recovered from the XTF headers by routines developed at ISMAR, and re-input to SEISPRO. The operation was also useful to check data integrity, other than for producing the navigation map and database.

OBS

A number of 10 LotOBS Sercel OBS (designed by IFREMER, Fig.9), were deployed. Tabs.7 and Fig.5) show positioning data, and techicak specifications s are reported in Tab.8). LotOBS is specialised for seismological data acquisition, uses the same acquisition electronics as in the previously developped MicrOBS. In order to include sufficient batteries to be able to record for 8 months (during a deplyment period of up to 12 months) the instrument is housed in a 17 inch glass sphere with a weight in air of about 50 kg. The external 4.5 Hz geophones are deployed briefly after the arrival of the instrument on the sea-floor.

**Figure 9:** OBS at launch.
$\begin{figure}\centerline{\epsfig{file=IMG/OBS_DROP.eps,width=0.5\linewidth}} \end{figure}$

Table 7: OBS drop positions. Latitude, Longitude true position, Time UTC

LON LAT	DATE_TIME	OBS	NOTES
2725.3936 4044.2150	2009-09-27T03:06:04	OBS01	S/N-LV03 0x094 F73 F71
2729.9079 4049.5494	2009-09-27T04:45:42	OBS02	S/N-LV11 0x09C F83 F81
2742.0275 4051.8859	2009-09-27T06:16:09	OBS03	S/N-LV02 0x093 F70 F6E
2749.7209 4044.4076	2009-09-27T07:19:41	OBS04	S/N-LV07 0x098 F7B F79
2818.5332 4046.5612	2009-09-27T09:48:00	OBS05	S/N-LV12 0x09D F84 F82
2834.6671 4044.3661	2009-09-27T11:18:06	OBS06	S/N-LV09 0x09A F7F F7D
2847.8779 4045.5176	2009-09-27T17:19:18	OBS07	S/N-LV05 0x096 F77 F75
2825.9607 4052.0406	2009-09-27T20:03:59	OBS08	S/N-LV08 0x099 F7C F7A
2907.0253 4043.1647	2009-09-28T11:54:17	OBS09	S/N-LV10 0x09B F80 F7E
2855.6879 4049.9109	2009-09-28T17:33:18	OBS10	S/M-LV01 0x092 F6F F6D

Table 8: IFREMER's SERCEL LOTOBS technical specifications.

General	Profondeur maxi.	5000 m
	Poids dans l'air	50 kg
	Poids dans l'air avec lest	75 kg
	Poids dans l'eau	-8 kg
	Poids dans l'eau avec lest	17 kg
	Dimensions (H / L / I)	L 550 x l 550 x H 700 mm
Capteurs	4 composantes	1 hydro et 3 geophones
	Sensibilité hydro	- 160 dB ref. 1 mV/microPa
	Hydrophone LF-3dB	2 Hz
	Hydrophone signal pleine échelle	70 Pa
	Géophones	3 axes
	Type géophones	4,5 Hz (-3 dB)
	Géophone sensibility	22,4 mV/mm.s-1
	Géophone pleine échelle	+/- 0,38 mm.s-1
	Orientation	Compas 3 axes
Acquisition	Canaux sismiques	4
	Résolution	24 bits
	Fréquence d'échantillonnage	25 à 250 Hz
	Bande de mesure	DC to 0,40 x f echantillonnage
	Gain du préamplificateur	Variable de 1 à 64
	Horloge	3.10-7 (0,3 ppm) ou 5.10 $^{-8}$
	Correction de dérive d'horloge	Correction lineaire de la derive
	Interface de synchronisation	DCF 77 (signal GPS)
	Stockage	32 Go (disque IDE SSD)
	Interface de configuration	RS232 (9 600, 1, 1)
Energy	Pack pile alcaline ou lithium	Pile Li-lon
	Consommation électrique	0,7 W recording, 0,3 W low power
	Autonomie	de 1 à 12 mois
Localisation Flash	Novatech (ST 400-A)
Gonio VHF	Novatech RF700A-1VHF 156,625 MHz

PIEZOMETERS

The IFREMER piezometer (V2) is a device to measure the differential pressure and temperature at different levels in the sediment, for long term duration periods, after wich system is recovered at surface by acoustic release. Its applications are relative to geohazards including slope stability and relations between seismicity and fluids. The deployment duration can be up to 2 years (batteries and memory). The system is deployed on the bottom by the ship in station, and released upon satisfactory check of its attitude, principally verticality, to assure proper functioning during the mission. The pipe and data logger head are handled and prepared for launch by a lodging device transported over a frame firmly secured to the ship stern's deck by steel angular, plates, T frames (See Fig.12, 13 and 14).

**Figure 10:** Sketch of the Piezometer deployment.
$\begin{figure}\centerline{\epsfig{file=IMG/PIEZO_SKETCH.eps,width=0.75\linewidth}} \end{figure}$

**Figure 11:** Sketch of the Piezometer deployment.
$\begin{figure}\centerline{\epsfig{file=IMG/PIEZO_SKETCH_1.eps,width=0.75\linewidth}} \end{figure}$

After installation of launch system on the deck of the R/V Urania, the piezometer deployment was firstly tested when ship was docked at Çannakale 2009-10-26. The operations on deck were performed by using the ship's main winch for the deployment and the SideScanSonar lateral winch laying Dynema and polyester ropes for the handling of the dead weight and buoy, as it is shown in the sketches of Fig.10 and 11. The final set-up was achieved by slight adjustements of the supporting frame on deck and of cable lengths from the auxiliary and main winch. The deployment of piezometers took place from 2009-09-27 up to 2009-09-30. After final checks of the selected sites by multibeam and CHIRP investigations , ship was put in station and the piezometer was : (a) put at 30-50m above the seafloor for 10 minutes for stabilization, (b) deposited on the seafloor, (c) decoupled from ship by delivering 30m of cable and (d) released after interrogation by acoustic modem with acceptable response on instrument's attitude and proper functioning. Table 10 gives detailed information on the whole operation.

Five Piezometers were deployed in the ÇinarcikBasin and near the SN4 site. Tab.9 and Fig.5 show the positioning data

**Figure 12:** Piezometer being prepared on the launch frame.
$\begin{figure}\centerline{\epsfig{file=IMG/PIEZOMETER_ON_DECK.eps,width=0.65\linewidth}} \end{figure}$

**Figure 13:** Piezometer being put vertical for launch by the oleopneumatic pistons.
$\begin{figure}\centerline{\epsfig{file=IMG/PIEZO_2.eps,width=0.5\linewidth}} \end{figure}$

**Figure 14:** Piezometer ready for launch.
$\begin{figure}\centerline{\epsfig{file=IMG/PIEZO_1.eps,width=0.5\linewidth}} \end{figure}$

Table 9: Piezometer bottom positions. Latitude, Longitude true position, Time UTC. Also shown associated Core,OBS and CHIRP file.

LON LAT	DATE_TIME	PIEZO	CORE	OBS	CHIRP	NOTES
2847.8665 4045.5046	2009-09-27T15:36:01	PZ-A	MPZ-01	OBS07	MA09-066(842)	S/N-01 1693 1649 1655
2907.0277 4043.1575	2009-09-28T08:39:32	PZ-B	MPZ-02	OBS09	MA09-103(2040)	S/N-02 1691 1649 1655
2907.2033 4044.0456	2009-09-28T13:05:47	PZ-C	MPZ-03	OBS09	MA09-112(2110)	S/N-03 1692 1649 1655
2923.1742 4043.6853	2009-09-29T07:48:34	PZ-D	MPZ-04	SN4	MA09-177(350)	S/N-05 1695 1649 1655
2856.2232 4050.0033	2009-09-29T12:48:18	PZ-E	MPZ-05	OBS10	MA09-188(760)	S/N-04 1690 1649 1655

Table 10: Detailed information of piezometer deployment.

Heure	Operation
10h30	Début de l'opération de mise à l'eau, le câble acier grand fond est dans l'axe, la laisse piézomètre est sur le treuil de maneuvre. Débordement du chariot, piézomètre lie au cable grand fond, et au treuil de man $\oe$ uvre. Mise à l'eau du piézomètre sur le câble grand fond dans l'axe du bateau, après immersion du piézomètre, palier de 5 minutes pour remplissage. Basculement du poids du piézomètre sur le câble de man $\oe$ uvre ( coté bâbord), le piézomètre quitte l'axe du bateau. Il peut être utile d'assurer le passage sur bâbord avec un cordage supplémentaire que l'on man $\oe$ uvrera sur le cabestan. On remonte le chariot de mise à l'eau (le train). On remonte le piézo par le ceble de maneuvre, pour libérer le câble grand fond.
10h50	Filage du piézomètre sur le câble de man $\oe$ uvre, à mis parcours mise en place du flotteur, puis filage du reste de la laisse jusqu'au niveau du tableau arrière du bateau. Sur le câble principal mise en place du lest dépresseur. Changement de main, on repasse le poids du piézomètre sur le câble principal grace à la patte d'oie en haut de la laisse. Le piézomètre repasse dans l'axe du câble grand fond.
11h05	Le filage peut commencer Le filage s'effectue à une vitesse de 1 m/s, le treuil grand fond fourni une information sur la longueur filée que l'on utilise pour le palier fond. La précision de cette information est trs relative. On arrête le filage 100 m avant le fond pour un palier de 10 minutes. Le piézo est alors a 50m du fond.
11h35	Reprise du filage pour enfoncement. Surveiller de très prêt le poids sur le câble pour bien déterminer le moment de l'enfoncement de la pointe, filer 10m de plus.
11h50	Vérifier l'horizontalité du largueur acoustique du lest (038C + 0349), puis larguer le lest (038C+0355).Décoller le lest du fond, comme la mer est calme la vitesse du treuil est entre 0,2 et 0,5 m/s. Remonté du lest à la vitesse max du treuil : 1,5m/s.
12h10	Il faut à nouveau faire un changement de main, on peut utiliser la grue pour sortir le lest de l'eau et le positionner à la verticale sur le pont sur l'électronique du piézo suivant.

SN4 BOTTOM OBSERVATORY

The INGV and TECNOMARE SN-4 observatory was developed in the framework of ORION (Ocean Research by Integrated Observatory Networks) EC project and deployed as node of ASSEM (Array of Sensors for long-term SEabed Monitoring of geohazards) EC project during a joint experiment in the Corinth Gulf (Greece, 400 m w.d.) in 2004 [Favali and Beranzoli (2008)], proving compatibility of GEOSTAR-class observatories with other networks.

All sensors installed on the observatory are managed by dedicated low-power electronics, able to perform the following tasks: (a) management and acquisition from all scientific packages and status sensors; (b) event detection; (c) preparation and continuous update of hourly data messages; (d) management of bidirectional communications via hydro-acoustic telemetry link (including transmission of seismic wave forms); (e) actuation of commands received (e.g., data request, system reconfiguration, restart) and (f) complete data back-up on internal memory. The SN-4 electronics can manage a wide set of data streams with quite different sampling rates tagging each datum according to a unique reference time set by a central high-precision clock.

During its first mission in Corinth Gulf SN-4 was equipped with a 3-C broad-band seismometer, an hydrophone and a methane sensor, with one year autonomous operation with 12-V, 960-Ah lithium battery pack. To reduce disturbance of the frame and electronics, special devices were designed and implemented for installing the seismometer, which is lodged in a dedicated vessel integrated in a separate structure connected to the SN4 by a special mechanical release. To guarantee a good coupling with the sea bottom, the structure is disconnected just after the touch-down and kept linked to the frame by a slack rope. This method of seismometer installation proved to record higher quality data during all the GEOSTAR-class observatory missions. For the Marmara mission the configuration of the SN4 was modified, aiming at better quantifying the temporal relations between fluid expulsion, fluid chemistry and seismic activity along the NAF. The new payload and relevant sampling rates are summarised in Tab.11. The station will be deployed using ship's winch and an acoustic release like in ASSEM mission, but the recovery procedure was redesigned, i.e. station will be recovered by a rope released by an acoustic command, letting the operations be performed by ship-of-opportunity. To achieve this result, the total weight in water was reduced to 0.15kN ( $\approx$ 150 kg)from the 500kg in air by installing 8 benthospheres on the frame and adopting new lighter vessels for batteries and Electronics. This new fitting will make recovery and redeployment eeasier at the end of scheduled 6 months of activity . For future applications, SN-4 can be re-configured to operate as cabled observatory for permanent long-term real-time monitoring of the Marmara Sea to study relationship between fluids and seismicity.

**Figure 15:** SN4 sketches.
$\begin{figure}\centerline{\epsfig{file=IMG/SN4_configuration_nohydro.eps,width=0.9\linewidth}} \end{figure}$

MEDUSA TOWED OBSERVATORY

During deployments, a hose was wrapped on the umbilical at the frame and to a surface pump for water sampling at interesting quotes or whenever dictated by Real Time data, especially increase in methane concentration.

**Figure 16:** INGV's MEDUSA being deployed.
$\begin{figure}\centerline{\epsfig{file=IMG/MEDUSA_01.eps,width=0.5\linewidth}} \end{figure}$

SEABED SAMPLING

The sea bottom samples were collected with 1.2 Ton gravity corer (Fig.18), the ISMAR's Mod.SW-104 water/sediment corer [Magagnoli A. and Mengoli M. (1995)] (Fig.17) and with a box corer (Fig.17).

**Figure 17:** SW-104 water/sediment corer and box corer.
$\begin{figure}\epsfig{file=IMG/SW-104_1.ps,width=0.5\linewidth} \epsfig{file=IMG/BC.eps,width=0.5\linewidth} \end{figure}$

**Figure 18:** Gravity corer.
$\begin{figure}\centering \epsfig{file=IMG/CORE.eps,width=0.6\linewidth} \end{figure}$

Table 13: Bottom sample positions. Latitude, Longitude true position, Time UTC

LON LAT	DATE_TIME	CORE	LENGTH	COMMENT
2847.8815 4045.5070	2009-09-27T13:18:01	MPZ-01-	3.20m	- -
2847.8665 4045.5046	2009-09-27T15:36:01	PZ-A-	S/N-01	1693 1649
2907.0277 4043.1575	2009-09-28T08:39:32	PZ-B-	S/N-02	1691 1649
2906.9286 4043.1818	2009-09-28T11:09:21	MPZ-02-	3.24m	- -
2907.2033 4044.0456	2009-09-28T13:05:47	PZ-C-	S/N-03	1692 1649
2907.2564 4044.0267	2009-09-28T14:30:23	MPZ-03-	2.22m	- -
2923.1766 4043.6859	2009-09-29T06:19:45	MPZ-04-	2.97m	- -
2923.1742 4043.6853	2009-09-29T07:48:34	PZ-D-	S/N-05	1695 1649
2856.2232 4050.0033	2009-09-29T12:48:18	PZ-E-	S/N-04	1690 1649
2856.1343 4049.9861	2009-09-29T14:04:03	MPZ-05-	3.48m	- -
2923.0715 4043.7790	2009-10-03T06:22:15	MSN-BC01-	0.18m	oxic
2923.0737 4043.7880	2009-10-03T07:02:42	MSN-BC02-	0.24m	anoxic
2923.2642 4043.7372	2009-10-03T08:57:43	MSN-C01-	1.00m,	extruded pw
2923.2519 4043.7479	2009-10-03T10:13:11	MSN-C02-	2.04m
2923.2456 4043.7445	2009-10-03T11:28:35	MSN-C03-	2.02m
2923.3125 4043.7381	2009-10-06T08:01:09	MSN-SW01-	0.73m	extruded pw
2923.3166 4043.7361	2009-10-06T08:44:05	MSN-SW02-	0.70m	- -
2927.4719 4043.7841	2009-10-06T10:08:18	MSP-C01-	2.24m
2927.4790 4043.7832	2009-10-06T11:47:57	MSP-C02-	1.85m	Large
2830.2163 4052.2810	2009-10-07T12:22:24	MEI-C01-	2.73m
2830.2213 4052.2798	2009-10-07T12:55:30	MEI-SW01-	1.30m
2830.2238 4052.2782	2009-10-07T13:39:20	MEI-C02-	2.92m
2832.5955 4056.3491	2009-10-07T14:53:04	MEI-SW02-	0.70m

MISCELLANEOUS

The WGS84 datum, the UTM35N projection and UTC were chosen for navigation and display, and for data acquisition. The time zone was set to the UTC for the instrumental data acquisition. The positioning maps and bathymetric images were produced with GMT [Wessel and Smith (1995)] and Globalmapper. The multibeam data were pre processed on board by the GMT software and ISMAR's routines and scripts, using the SIS production DTMS, after conversion to the ASCII format.

Bathymetric data were complemented by the IFREMER's DTM of Sea of Marmara [Le Pichon et al.(2005)]. On-land SRTM topography data was used for mapping, structural analysis, after conversion to NETCDF GMT grid files.

The computing center employed INTEL based PC running the GNU-Linux in addition to portable computer for data acquisition and personal processing. The Linux machines were used as data repositories using the SAMBA software, providing alse network services like WWW, DHCP and NAT.

Photographs and video were taken by digital cameras and video-camera by INGV dedicated personnel and by all participants.