Exploring the «inaccessible» part of the Artic Ocean by exploting the logistic advantages of the drifting sea ice

"Fly in, drift out"

Scientific objectives:
Late Cretaceous/Early Cenozoic tectonic events in West Spitsbergen, Northeast Greenland and Ellesmere Island are time equivalent, but the related offshore tectonic structures are unknown.

Geophysics:
    to acquire seismic reflection and velocity information to:

1. assess how the predicted compressional deformation is manifested in the complex tectonic structures collectively called the Morris Jesup Plateau north of Greenland (Fig. 2), and
2. establish the origin of the eastern part, the Morris Jesup Spur and the extent of early Tertiary volcanism.
3. make video recordings of the seabed at intervals along the drift transect.

Oceanography:

1. make measurements of temperature and salinity to full ocean depth along the drift transect.

Marin biology:

1. Profiling the water column to 1500 m. depth with a high frequency echosounder to explore for presence of marine life.
2. Video recording of fauna and flora in the scattering layer (upper 100 m) using an underwater drone.

Sea ice:

1. time lapse surveillance of the local ( 1 x 1 km) environment by drone
2. time lapse surveillance of the environment along the 7 km long seismic array
3. underwater drone observation of ice ridging in progress

The scientific basis for our project is to explore the offshore tectonic and depositional elements related to the separation of Greenland, Svalbard and the Canadian Arctic Islands during he Late Cretaceous/Early Cenozoic. Tectonic events in West Spitsbergen, Northeast Greenland and Ellesmere Island are time equivalent, but the related offshore tectonic structures are unknown.

Fram-2020 Geophysical objectives:
Acquire seismic reflection and velocity information to:

1. assess how the predicted compressional deformation is manifested in the complex tectonic structures across Morris Jesup Plateau north of Greenland.
2. establish the origin of the Morris Jesup Spur and the extent of early Tertiary volcanism.

Small source, single channel data, in low noise environment bellow the ice gives surprisingly good data

Fram-2020 introducing TASSS:

• the most advanced seismic acquisition experiment on drifting ice ever
• 70 autonomous hydrophone-nodes, 6 km in-line offset, 1,2 km x-line offset
• Dual source, 20 cub. Inch, 12.5m sp interval, flip-flop, 30 m gun separation
• Resulting in a high resolution 3D swath along the drift path 12,5 x 15m bin
• 600 m wide bathymetric swath achieved by dense x-line spacing and dual-source
• Seismic reflection and refraction velocities from long-offset layout

Fram-2020 Science

Advantages of an ice covered ocean
The drifting sea ice in the Arctic Ocean is considered an obstacle to seismic exploration, but does never the less have two important advantages. Firstly, sea ice drift is mostly coherent over areas of tens of kilometers (Fig. 3) and enable you to maintain extended moving arrays not possible in the open ocean. In 1982 we successfully collected >200 km of multichannel seismic data using a 2 km linear array of 20 sonobuoys operating for a month (Kristoffersen and Husebye, 1984). Secondly, the ambient noise level below the sea ice lid is below sea state 0 in the open ocean. The past Fram- 2014/15 ice drift took advantage of this and collected 1000 km of seismic data using a 20 cuinch air gun and a single hydrophone to achieve 2 km of sub-bottom penetration in 3 km water depth.

Safety
The sea ice is a safe place. Nothing hits you. Opening of cracks or compressive motion in ridges involve relative motion of the order of a meter minute. First year ice 1.4 m thick has the strength and carrying capacity required to land a Boing 737 aircraft. In the more than 50-year history of ice drift stations, we do not know of lives lost due to ice movement. Lives lost have been related to helicopter or aircraft operations.
The planned Fram-2020 ice camp will report to regional rescue centers and be within reach of the Super Puma rescue helicopter stationed in Longyearbyen, via Greenland. The area of operation will experience the midnight sun and full daylight for the duration of the project.

The legacy
The Arctic Ocean has experienced a 20-year period with annual seismic surveys by icebreakers driven by the need for documentation required to extend the EEZ. This activity has now ended, but at the same time outlined the limits of the capacity for seismic data acquisition by icebreakers. Unless an ice drift approach is used, the area north of Canada and north of Greenland will remain unexplored for decades to come. We expect the Fram-2020 expedition and use of nodes will demonstrate the potential for data quality combined with a lean logistic approach as an attractive method to explore the remaining inaccessible areas of the Arctic Ocean.