scholarly journals 2D seismic exploration of the Ancona landslide (Adriatic Coast, Italy)

Geophysics ◽  
2009 ◽  
Vol 74 (5) ◽  
pp. B139-B151 ◽  
Author(s):  
Eusebio Stucchi ◽  
Alfredo Mazzotti
Keyword(s):  
Seismic Reflection ◽  
Seismic Exploration ◽  
Data Sets ◽  
Air Gun ◽  
Combined Use ◽  
Landslide Body ◽  
Adriatic Coast ◽  
Seismic Reflection Profiles ◽  
Detachment Surface ◽  
Ancona Landslide

We have used on- and offshore seismic reflection profiles to determine the extension of a historic landslide at depth and toward the sea. The subsurface landslide structure was delineated by using four separate data sets produced by the combined use of geophone and hydrophone spreads, and of explosive and air-gun sources which also illuminated, through an undershooting configuration, the subsurface below the coastal road and railway. Many noise problems related to the source and environment were overcome and alleviated with several signal-processing routines. The resulting stack and depth-migrated sections reveal the deep geometry of the main landslide body and indicate the emergence location, at the landslide foot, of a deep, potential detachment surface, which previous investigations failed to evidence.

Phanerozoic vertical motions of Hudson Bay

2004 ◽  
Vol 41 (10) ◽  
pp. 1181-1200 ◽  
Author(s):  
Detlef Hanne ◽  
Nicky White ◽  
Andrew Butler ◽  
Stephen Jones
Keyword(s):  
Seismic Reflection ◽  
Hudson Bay ◽  
Data Sets ◽  
Reflection And Refraction ◽  
Crustal Thinning ◽  
Basin Subsidence ◽  
Starting Point ◽  
Intracratonic Basin ◽  
Seismic Reflection Profiles ◽  
Two Stages

We analyze the sedimentary record of the Hudson Bay basin, an intracratonic basin which is widely believed to have been formed by convective downwelling within the mantle. This belief largely stems from the coincidence of a long-wavelength negative gravity anomaly and an approximately circular basin which is filled with about 2 km of predominantly Paleozoic sedimentary rocks. Our starting point is a set of wells and seismic reflection profiles which demonstrate that the basin subsided rapidly from Ordovician to Devonian times. One- and two-dimensional subsidence modeling show that water-loaded subsidence occurred in two stages and is too rapid to be accounted for by thermal contraction alone. Instead, we suggest that basin subsidence is consistent with minor phases of lithospheric thinning which occurred during Ordovician–Silurian and Early–Middle Devonian times. Stretching factors for these minor extensional episodes vary from 1.05 to 1.2 with vertical strain rates of 2–10 Ga–1. Our interpretation of the subsidence record is corroborated by limited evidence for syn-rift normal faulting and crustal thinning inferred from legacy seismic reflection and refraction data sets. Subsidence modelling also suggests that about 1 km of expected thermal subsidence is missing. This discrepancy suggests that the basin was uplifted and denuded at least once, but possibly several times, between Late Devonian and Middle Cretaceous times (i.e., 360–100 Ma) and between Cretaceous and Quaternary times. We conclude that the Hudson Bay basin was not generated by convective downwelling that initiated in Paleozoic times and that remained coupled to the lithospheric plate.

Seismic investigations of sedimentary structure in the northern Rockall Trough—a synopsis

1986 ◽  
Vol 88 ◽  
pp. 53-54
Author(s):  
R. J. Whittington ◽  
M. R. Dobson
Keyword(s):  
Seismic Reflection ◽  
Single Channel ◽  
Sedimentary Structure ◽  
The North ◽  
Air Gun ◽  
Late Tertiary ◽  
Rockall Trough ◽  
Seismic Reflection Profiles ◽  
Small Capacity ◽  
North Rockall Trough

Single channel, analogue, seismic reflection profiles using Sparker and small capacity Air gun sources were used to investigate late Tertiary and Quaternary sedimentation both around the margins and on the floor of the north Rockall Trough. The data complement, by being intermediate in penetration and resolution, previous seismic studies; particularly, they allow the upper 500 m of the sediment sequence to be examined in greater detail than hitherto.

scholarly journals Cost-Effective Seismic Exploration: 2D Reflection Imaging at the Kylylahti Massive Sulfide Deposit, Finland

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 263 ◽  
Author(s):  
Suvi Heinonen ◽  
Michal Malinowski ◽  
Felix Hloušek ◽  
Gardar Gislason ◽  
Stefan Buske ◽  
...  
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Imaging Techniques ◽  
Mineral Exploration ◽  
Massive Sulfide ◽  
Seismic Profile ◽  
Seismic Exploration ◽  
Sulfide Deposit ◽  
Depth Imaging ◽  
Seismic Reflection Profiles

We show that by using an advanced pre-stack depth imaging algorithm it is possible to retrieve meaningful and robust seismic images with sparse shot points, using only 3–4 source points per kilometer along a seismic profile. Our results encourage the use of 2D seismic reflection profiling as a reconnaissance tool for mineral exploration in areas with limited access for active seismic surveys. We used the seismic data acquired within the COGITO-MIN project comprising two approximately 6 km long seismic reflection profiles at the polymetallic Kylylahti massive sulfide mine site in eastern Finland. The 2D seismic data acquisition utilized both Vibroseis and dynamite sources with 20 m spacing and wireless receivers spaced every 10 m. For both source types, the recorded data show clear first breaks over all offsets and reflectors in the raw shot gathers. The Kylylahti area is characterized by folded and faulted, steeply dipping geological contacts and structures. We discuss post-stack and pre-stack data processing and compare time and depth imaging techniques in this geologically complex Precambrian hardrock area. The seismic reflection profiles show prominent reflectors at 4.5–8 km depth utilizing different migration routines. In the shallow subsurface, steep reflectors are imaged, and within and underneath the known Kylylahti ultramafic body reflectivity is prominent but discontinuous.

scholarly journals Spatial Relationships between Pockmarks and Sub-Seabed Gas in Fjordic Settings: Evidence from Loch Linnhe, West Scotland

Geosciences ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 283
Author(s):  
Allan Audsley ◽  
Tom Bradwell ◽  
John Howe ◽  
John Baxter
Keyword(s):  
Water Column ◽  
Seismic Reflection ◽  
Hot Spot ◽  
Geophysical Data ◽  
Spatial Relationships ◽  
Hydrocarbon Gases ◽  
Offshore Industry ◽  
Seismic Reflection Profiles ◽  
Spot Analysis ◽  
Sedimentary Carbon

Sub-seabed gas is commonly associated with seabed depressions known as pockmarks—the main venting sites for hydrocarbon gases to enter the water column. Sub-seabed gas accumulations are characterized by acoustically turbid or opaque zones in seismic reflection profiles, taking the form of gas blankets, curtains or plumes. How the migration of sub-seabed gas relates to the origin and distribution of pockmarks in nearshore and fjordic settings is not well understood. Using marine geophysical data from Loch Linnhe, a Scottish fjord, we show that shallow sub-seabed gas occurs predominantly within glaciomarine facies either as widespread blankets in basins or as isolated pockets. We use geospatial ‘hot-spot’ analysis conducted in ArcGIS to identify clusters of pockmarks and acoustic (sub-seabed) profile interpretation to identify the depth to gas front across the fjord. By combining these analyses, we find that the gas below most pockmarks in Loch Linnhe is between 1.4 m and 20 m deep. We anticipate that this work will help to understand the fate and mobility of sedimentary carbon in fjordic (marine) settings and advise offshore industry on the potential hazards posed by pockmarked seafloor regions even in nearshore settings.

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