OBS Characteristics and deployment

Table A5: OBS Characteristics.

Seismic sensor gimballed	Guralp CMG40T-OBS, 3C seismometer with a flat response between 60s and 100Hz, housed in a 16 cm of diameter spherical casing (6000m depth rated) and installed on a levelling platform with an operational tilt range of $\pm$ 120°
Pressure sensor	Cox-Webb Differential Pressure Gauge 500s-2 Hz; gain 1 mV/Pa at 1 Hz on OBS A2, A4, A5, A6 HTI-04-PCA/ULF Hydrophone 100s-8KHz; sensitivity: -195 dB re: 1V/ $\mu$ Pa (18V/bar) on OBS A7
Temperature logger	On OBS A7, a Tinytag ACS-0001-PK was installed. The deep water data logger kit contains a compact 16-bit data logger with a capacity of 16,000 readings, housed within a stainless steel canister designed to withstand depths up to 10km
Digitizer	SEND Geolon MLS 21 bits digitizer, 4 channels (3 for the seismometer and 1 for the hydrophone or DPG). Sampling rate up to 200 sps
Clock	Seascan Precision Time base. Time base drift 0.05 ppm
Storage Capacity	12 PCMCIA slots, up to 24 GB with 2GB flash cards.
Battery Packs	2 Primary Lithium-Thionyl Chloride battery packs of 14,4 V and 350 Ah
weight	450/36,5 Kg in air/water
Electronic canister	ERGAL canister (7075 T6 aluminium alloy), with hard anodizing.
Release system	IXSEA AR861S-MR and C980102 ORE-Offshore acoustic release system.
Emergency localization system	ELSACOM Guardian Sentinel, to transmit the OBS positions every 3 hours for more than one month, if it comes back on the sea surface.
OBS dimensions	1200x800x1500 mm

Table A6: OBS deployment data and Digitizer settings.

OBS Serial Number	A4
Lon Lat Time	1527.0056075 3840.0078879 05/02/2010 18.07.34
Synchronization time	05/02/2010 14:51:00
Seismometer release	06/02/2010 00:30:00
Start recording	05/02/2010 16:23:20
Levelling	Every 30 days and after 12 hours from start recording
Sampling Freq.	100 Hz
OBS Serial Number	A2
Lon Lat Time	1420.0891942 3852.9956644 06/02/2010 00.36.41
Synchronization time	05/02/2010 20:57:00
Seismometer release	06/02/2010 06:00:00
Start recording	05/02/2010 22:46:11
Levelling	Every 30 days and after 12 hours from start recording
Sampling Freq.	100 Hz
OBS Serial Number	A5
Lon Lat Time	1447.1151862 3901.9706885 14/02/2010 09.42.02 GPST 094238
Synchronization time	14/02/2010 08:29:00
Seismometer release	14/02/2010 14:30:00
Start recording	14/02/2010 08:33:00
Levelling	Every 30 days and after 12 hours from start recording
Sampling Freq.	100 Hz
OBS Serial Number	A7
Lon Lat	1423.6013304 3916.4010778 14/02/2010 14.33.46)143410GPS
Synchronization time	14/02/2010 13:50:00
Seismometer release	14/02/2010 19:50:00
Start recording	14/02/2010 13:53:25
Levelling	Every 30 days and after 12 hours from start recording
Sampling Freq.	100 Hz
OBS Serial Number	A6
Lon Lat	1359.9912974 3929.9972205 (14/02/2010 17.50.17)175049GPS
Synchronization time	14/02/2010 16:03:00
Seismometer release	15/02/2010 00:00:00
Start recording	14/02/2010 16:06:52
Levelling	Every 30 days and after 12 hours from start recording
Sampling Freq.	100 Hz