Seismoacoustic Study of the Shallow Gas Transport and ... - E-LIB

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Chapter 2 times. Seismically imaged normal faults cut the Quaternary sediments, suggesting possible reactivation of the West Crimean fault (Limonov et al., 1997; Finetti et al., 1988; Slack et al., 1998). The mud volcanoes in the central Black Sea are well expressed on the sea bottom as chamber-shaped features of 300-2000 m diameter and up to 120 m height. Some of them have craterlike depressions on the top with rims. The feeder channels of the mud volcanoes vary in diameter from several hundred meters to 3.5 km (Gaynanov et al., 1998). The roots of these mud volcanoes are not exactly known, but their origin is clearly related to the layers of plastic clay of the Maikopian Formation (Ivanov et al., 1996), which are highly enriched in organic matter (Dimitrov, 2002). 2.3. Previous acoustic studies Mud volcanoes in the central Black Sea which were first discovered and sampled at the end of the 1980s by the Geological Faculty of Moscow State University (MSU) and Yuzhmorgeologiya, and were named as Kornev, Goncharov, Malyshev, MSU, Yuzhmorgeologiya and Vassoevitch (Ivanov et al., 1989). Hydroacoustic studies of mud volcanoes in the central Black Sea were carried out during Cruises TTR-1, TTR-3, TTR-6 and TTR-11 in 1991, 1993, 1996 and 2001 as part of UNESCO “Training-through-Research” program (Ivanov et al., 1996; Limonov et al., 1997; Dimitrov, 2002). Mud volcanoes occur in the central part of the Black Sea in a great variety of sizes, up to 2.5 km in diameter, and they may rise more than 120 m above the seafloor. Morphologically, they can be subdivided into three types (Ivanov et al., 1996): the first type includes the largest mud volcanoes, Yuzhmorgeologiya and MSU, with a seabed diameter of ~4 km and a relative height of ~100 m. Both mud volcanoes are gentle structures with complex craters. Mud volcanoes Kornev, Malyshev and Goncharov represent the second type. They have a diameter between 1.7 and 3.8 km at the base and a height of 100 m above the seafloor, with relatively steep flanks. The third type includes the Vassoevitch mud volcano, with a very distinct, irregular shape and a collapse structure. During RV Meteor Cruise M52/1, seismic lines were shot across these six mud volcanoes in WNW to ESE direction. Lines shot during the TTR-1 Cruise revealed a shallower penetration of ~0.9 s than the new GI Gun data with 2 s. Furthermore, compared to ~15 m vertical resolution of the TTR data, the new GI gun data provided a higher vertical resolution of ~7 m. 2.4. Materials and methods A 2D high-resolution seismic data set was collected during R/V Meteor Cruise M52/1 in early 2002 (Krastel et al, 2003). A GI-gun (generator-injector gun, 2 x 1.7 L) towed in 1.4 m water depth was used as seismic source, generating main frequencies in the range 47
Chapter 2 of 50 to 500 Hz. The multichannel seismic streamer (SYNTRON) includes a tow-lead, a stretch section of 50 m and six active sections of 100 m length each. GI Gun data were recorded by a 600 m long streamer using 48 channels at a group distance of 12.5 m. The streamer was kept in a water depth of 3 m (+/- 0.5 m) by the attachment of 9 cable levelers (4 MultiTrak Remote Units (MTC birds) and 5 DigiCOURSE Birds (DigiBirds)). Positioning was based on GPS recordings. 11 seismic profiles were acquired in the central Black Sea. Figure 2 Bathymetry of the area of investigation in the central Black Sea together with the seismic lines (bathymetric data from Cruises TTR6, M52-1, M72-3, MSM15-2 and M84-2). Six mud volcanoes were mapped. The seismic data were processed, using the commercial software package Vista seismic processing. The custom-made WinGeoapp software was used for geometry calculation, CMP binning distance was chosen to be 10 m, leading to ~15-fold coverage. Dead and extremely noisy channels were removed from the data. Traces with random 48
Page 1: Seismoacoustic Study of the Shallow
Page 4 and 5: Table of contents Table of contents
Page 6 and 7: Abstract Abstract In recent years,
Page 8 and 9: Outline of the Dissertation Outline
Page 10 and 11: Chapter 1 Chapter 1. Introduction 1
Page 12 and 13: Chapter 1 reflections, interpreted
Page 14 and 15: Chapter 1 Submarine gas seeps, pock
Page 16 and 17: Chapter 1 which have documented act
Page 18 and 19: Chapter 1 fluid migration related t
Page 20 and 21: Chapter 1 Evidence of gas seepage
Page 22 and 23: Chapter 1 The three main different
Page 24 and 25: Chapter 1 from deeper sources in th
Page 26 and 27: Chapter 1 numerous countries such a
Page 28 and 29: Chapter 1 1.5 Geological setting of
Page 30 and 31: Chapter 1 main sequences consist of
Page 32 and 33: Chapter 1 craterlike depressions wi
Page 34 and 35: Chapter 1 Jurassic - Paleogene, Upp
Page 36 and 37: Chapter 1 respectively, and one wat
Page 38 and 39: Chapter 1 During the seismic data p
Page 40 and 41: Chapter 1 1.6.2 The Parasound sedim
Page 42 and 43: Chapter 1 Caress, D.W., and Chayes,
Page 44 and 45: Chapter 1 Hovland, M., Gardner, J.V
Page 46 and 47: Chapter 1 Luo, X.R. and Vasseur, G.
Page 48 and 49: Chapter 1 Schroot, B.M., Klaver, G.
Page 50 and 51: Chapter 2 Chapter 2. Shallow Gas Tr
Page 54 and 55: Chapter 2 spike noise were marked a
Page 56 and 57: Chapter 2 The 2D high resolution se
Page 58 and 59: Chapter 2 Figure 4 A close-up of se
Page 60 and 61: Chapter 2 within the upper sediment
Page 62 and 63: Chapter 2 volcanoes between 66 and
Page 64 and 65: Chapter 2 Figure 7 Geo-seismic sect
Page 66 and 67: Chapter 2 In the study area, many b
Page 68 and 69: Chapter 2 volcanism could be calcul
Page 70 and 71: Chapter 2 along the feeder channel
Page 72 and 73: Chapter 2 Evpatoriya). Soviet Geol
Page 74 and 75: Chapter 3 Chapter 3. Sedimentary Ev
Page 76 and 77: Chapter 3 South (Fig. 2). The water
Page 78 and 79: Chapter 3 Figure 3 (a) Uninterprete
Page 80 and 81: Chapter 3 Seven seismic facies type
Page 82 and 83: Chapter 3 Seismic Unit 5 ranges in
Page 84 and 85: Chapter 3 3.4.3.5. Seismic Unit 2 A
Page 86 and 87: Chapter 3 Figure 11 (a) Uninterpret
Page 88 and 89: Chapter 3 Figure 13 (a) Uninterpret
Page 90 and 91: Chapter 3 boundary between the Plio
Page 92 and 93: Chapter 3 Seismic Unit 6 belongs to
Page 94 and 95: Chapter 3 subsidence was coincident
Page 96 and 97: Chapter 3 Acknowledgements We thank
Page 98 and 99: Chapter 3 Tugolesov, D.A., Gorshkov
Page 100 and 101: Chapter 4 study area at ~900 m wate
Page 102 and 103:
Chapter 4 Figure 2 Bathymetry of th
Page 104 and 105:
Chapter 4 University of Bremen). At
Page 106 and 107:
Chapter 4 and Ridge R2 (GeoB07-139)
Page 108 and 109:
Chapter 4 flares location. Anticlin
Page 110 and 111:
Chapter 4 GeoB07-145. Green arrows
Page 112 and 113:
Chapter 4 4.4.3.2.3. Other anomalou
Page 114 and 115:
Chapter 4 Slope fan deposits with f
Page 116 and 117:
Chapter 4 Figure 12 Possible locati
Page 118 and 119:
Chapter 4 bulk hydrate or even high
Page 120 and 121:
Chapter 4 may add to gas accumulati
Page 122 and 123:
Chapter 4 The narrow-beam Parasound
Page 124 and 125:
Chapter 4 River fan deposits. Being
Page 126 and 127:
Chapter 4 Klaucke, I., Sahling, H.,
Page 128 and 129:
Chapter 4 Wagner-Friedrichs, M., 20
Page 130 and 131:
Chapter 5 deposited; during lowstan
Page 132 and 133:
Chapter 5 accumulations. An acousti
Page 134 and 135:
Acknowledgements Acknowledgements I
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