Transcript WP2_CSIC_Sallares - Integrated observations from NEAR shore

Task 2.2 Wide-Angle Seismic cruise
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Nearest - WP2
30 months Progress Report
Objectives
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Overall objective of WP2
Characterisation of the potential tsunami source areas
 Definition of the geometry and velocity structure of the
continental margin offshore SW Iberia
 Definition of the main plate limits and geological domains
 Relate earthquake and tectonic structures, specially the
deep décollement surfaces.

Integration of existing MCS data (SWIM, Rifano, IAM,
Sismar, etc) with newly acquired Wide-Angle Seismic
data (Nearest-Seis survey).
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Starting point
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Starting point (activities done in 2008)
State of knowledge concerning the main active,
potentially tsunamigenic structures > tectonic map as D1
 Legacy data of MCS profiles re-processed up to PSDM >
compilation as D4 (Task 2.1 -finished-)
 Preparation of the Nearest-Seis survey, including
assembly of instrumentation (OBS and guns), definition of
scientific and technical teams, lines, vessel schedule,
acquisition geometry, etc.

Nearest-Seis survey took place between Oct 27th and
Nov 11th on board R/V Hespérides
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Specific objectives
Specific objectives of Nearest-Seis
Provide information on
the physical properties of
the crust as well as the
crust-mantle boundary
geometry

Identify the nature of the
crust (eg. oceanic vs.
continental) and the limits
of the different crustal
domains

Obtain information to
construct a 3-D P-wave
velocity model to be used
to improve earthquake
locations (WP3)

Nearest 30 Months Meeting
Brest, April 2-3, 2009
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Meeting presentations
Bartolomé, R., Gràcia, E., Martínez-Loriente, S. and EVENT and NEAREST Teams (2009). Estructuras
activas en el Golfo de Cádiz, 1ª Reunión del Proyecto de Excelencia de la Junta de Andalucía RNM
3713, 12 March 2009, Granada, Spain.
Martínez-Loriente, S. (2009). Stratigraphy and structure of external Gulf of Cadiz from pre-stack depth
migrated seismic profiles (SWIM-2006) implications for earthquake and tsunami hazard in SW Iberia,
IPGP Doctoral Student Congress; 16-20 March 2009; Paris, France.
Publications
Martínez-Loriente, S. (2009) "Estratigrafia i estructura de la part externa del Golf de Cadis basades en
dades de sísmica de reflexió multicanal migrades en profunditat pre-stack". DEA report presented at the
University of Barcelona.
Martínez-Loriente, S., Gràcia, E., Bartolomé, R., Sallarès, V., Dañobeitia, J.J., and Swim-06 Cruise Party
(2008). Pre-stack depth migration seismic imaging of the Coral Patch Ridge and adjacent Horseshoe and
Seine Abyssal Plains (Gulf of Cadiz): Tectonic implications. Trabajos de Geología, ISSN: 0474-9588.
Falivene, O., Arbués, J., Ledo, J., Benjumea, B., Muñoz, J.A., Fernandez, O., Martínez-Loriente, S.
(2008). Synthetic seismic from outcrop-derived reservoir-scale facies models, the Ainsa turbidite system
(NE Spain). Submitted to AAPG Bulletin.
Task 2.2 Wide-Angle Seismic cruise
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Task 2.2 Wide-Angle Seismic cruise
Devoted to the acquisition of WAS data, together with
complementary swath bathymetry, sediment profiler, gravity data
Took place between Oct 27th
(Cartagena) and Nov 11th
(Cadiz) on board BIO
Hespérides:
Length: 82,5 m
Arm: 14,30 m
Military crew : 52
Sci/tech crew: 29
Widely used for Antarctic
operations
Main Spanish seismic ship to
date
Task 2.2 Wide-Angle Seismic cruise
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Scientific/technical teams
A total of 27 persons:
12 Scientific (9 institututions)
12 Technical (5 OBS, 4 gunners, 2 shooting, 1 acoustics)
3 journalists (ZDF)
Task 2.2 Wide-Angle Seismic cruise
Instrumentation
19 MicrOBS OBS from Ifremer/UBO
 17 LC2000 OBS from UTM-CSIC
 7 Hathor LEAS landstations (1 Hz)
 7 Bolt 1500LL guns (250-1000 c.i.)
 Simrad EM120 multibeam (12 kHz)
 Topas sediment profiler (3.5 kHz)
 BGM-3 gravimeter

OBS
Short period (4.5 Hz), 3 components
seismometer
 Hydrophone
 Differ in size, weight, functioning and
authonomy

Nearest 30 Months Meeting
Brest, April 2-3, 2009
Task 2.2 Wide-Angle Seismic cruise
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Gun array
4520 c.i. maximum (2 new guns were constructed), but only
3520 c.i. in most P1
 12 m depth (notch at 80 Hz), 90 s shooting interval
 Useful bandwith between 10-50 Hz (peak at 25 Hz)

Task 2.2 Wide-Angle Seismic cruise
Nearest 30 Months Meeting
Brest, April 2-3, 2009
WAS profiles
P1 is 350 km long, with 29 OBS separated 5 nm in average
 P2 is 260 km long, with 15 OBS (7 nm) and 7 landstations
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Task 2.2 Wide-Angle Seismic cruise
Nearest 30 Months Meeting
Brest, April 2-3, 2009
WAS profiles
P1 is ~coincident with PSDM MCS lines SW13 and IAM4
 P2 is coincident with PSDM MCS line SW01

Task 2.2 Wide-Angle Seismic cruise
WAS data along P1
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Task 2.2 Wide-Angle Seismic cruise
WAS data along P1
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Task 2.2 Wide-Angle Seismic cruise
WAS data along P1
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Task 2.2 Wide-Angle Seismic cruise
WAS data along P2
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Task 2.2 Wide-Angle Seismic cruise
WAS data along P2
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Task 2.2 Wide-Angle Seismic cruise
WAS data along P2
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Task 2.2 Wide-Angle Seismic cruise
WAS data along P2
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Task 2.2 Wide-Angle Seismic cruise
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Earthquakes recorded by OBS
Waveforms from OBSs 8 ( top), 13 (mid), 14 (bottom),
P1 profile (right).
Task 2.3 Processing and modelling
Nearest 30 Months Meeting
Brest, April 2-3, 2009
Task 2.3 Processing and modelling of WAS data
All data have been pre-processed (record sections
constructed, clock correction done, OBS relocated,
bandpass filtering done)
 P2 has been modeled (preliminary model by A. Gailler)
 P1 will be modeled by S. Martínez (starting next week)

Nearest 30 Months Meeting
Task 2.3 Processing and modelling
Brest, April 2-3, 2009
Gantt Table
Task\Month
2
4
6
8
10
12
14
16
18
20
22
x
x
x
x
x
x
x
x
x
24
26
28
x
x
x
x
x
WP2 Provisional
WP2 Actual
Task 2.1 Provisional
Task 2.1 Actual
Task 2.2 Provisional
Task 2.2 Actual
x
Task 2.3 Provisional
Task 2.3 Actual
30
32
34
36