Desktop studies

Desktop studies were developed during 2024, prior to data acquisition or sampling, and consisted on bibliographic review and interpretation of the existing information and data on:

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Geology

Preliminary technical reports on the geology of the areas were produced by the SEISLAB team using existing geophysical data.

>> PAER areas: Viana do Castelo, Figueira da Foz and Leixões

Aims:

  • Infer the expected thickness range of surficial sediments
  • Infer the existing lithologies
  • Help planning the 2024 and 2025 surveys

Datasets:

  • Scarse 2D high resolution vintage seismic data from the 90s
    • Original seismic data were in printed format
    • Converted to digital SEGY format
    • Positioned using navigation information and geometrical corrections
    • Sampling rates were homogeneized and missing data were interpolated
Onshore and offshore geological map of the surroundings of Figueira da Foz area. Data from EMODNet-Geology
Map of vintage data sets in the Figueira da Foz area
Onshore and offshore geological map of the surroundings of Leixões area. Data from EMODNet-Geology
Map of vintage data sets in the Leixões area
Onshore and offshore geological map of the North of Portugal. Data from EMODNet-Geology
Map of vintage data sets in the Viana do Castelo area
Example of vintage seismic data in the Leixões area and applied processing.
Top: original seismic profile in original printed format.
Center: restoration of the seismic line to a common depth scale, after conversion to seg-y data.
Bottom: Temptative processing of the seismic data (by the SEISLAB team).

MetOcean

A study on persistency analysis of MetOcean conditions was commissioned by IPMA to Hermess.

>> Four locations: PAER areas of Viana, Leixões, Figueira da Foz and Ericeira
(Ericeira was disconsidered after the 02/2025 revision of the PAER)

>> Time series analysis of 43 years data (1980-2023)

>> Determination of:

  • Workable 12h windows for operable wind and wave conditions
  • Expected delay waiting time (stand-by) for operable wind and wave conditions

>> Studied conditions for Wind speed (U) and significant wave height (Hs):

  • Hs < 1.5 m  &  U < 10 m/s (optimal conditions for data acquisition)
  • Hs < 2 m  &  U < 12 m/s (marginal conditions for data acquisition)
  • Hs < 1.5 m 
  • U < 10 m/s
  • Hs < 2 ma
  • U < 12 m/s
Four locations considered for MetOcean analysis

Archaeology

IPMA commissioned to ERA-Arqueologia a bibliographic research study on the potential of marine archaeological occurences in the PAER and surroundings areas.

>> PAER areas: Viana do Castelo, Figueira da Foz and Leixões

Aims:

  • Characterize the historical maritime use of the region
  • Identify the occurrence of potential archaeological sites in the study areas
  • Characterize the reference situation and classify the degree of impact of the work on heritage sites
  • Assess the potential presence of unexploded ordnances (UXO) amongst the identified occurrences
  • Define measures to minimize the impact of the work on cultural heritage

>> Potential occurences were classified according to the classes: shipwreck, aircraft crash, finding, undetermined.

List of information collected from the archeological databases
Areas considered for the Marine Archaeology desktop study. The regions between the coast and the PAER areas was also considered

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