Queen Charlotte fault zone: microearthquakes from a temporary array of land stations and ocean bottom seismographs

1981 ◽  
Vol 18 (4) ◽  
pp. 776-788 ◽  
Author(s):  
R. D. Hyndman ◽  
R. M. Ellis
Keyword(s):  
Fault Zone ◽  
Strike Slip ◽  
Ocean Bottom ◽  
Small Component ◽  
Queen Charlotte Islands ◽  
The North ◽  
Vertical Fault ◽  
Linear Sections ◽  
Ocean Bottom Seismographs ◽  
Steep Slopes

A temporary array of land and ocean bottom seismograph stations was used to accurately locate microearthquakes on the Queen Charlotte fault zone, which occurs along the continental margin of western Canada. The continental slope has two steep linear sections separated by a 25 km wide irregular terrace at a depth of 2 km. Eleven events were located with magnitudes from 0.5 to 2.0, 10 of them beneath the landward one of the two steep slopes, some 5 km off the coast of the southern Queen Charlotte Islands. No events were located beneath the seaward and deeper steep slope. The depths of seven of these events were constrained by the data to between 9 and 21 km with most near 20 km. The earthquake and other geophysical data are consistent with a near vertical fault zone having mainly strike-slip motion. A model including a small component of underthrusting in addition to strike-slip faulting is suggested to account for the some 15° difference between the relative motion of the North America and Pacific plates from plate tectonic models and the strike of the margin. One event was located about 50 km inland of the main active zone and probably occurred on the Sandspit fault. The rate of seismicity on the Queen Charlotte fault zone during the period of the survey was similar to that predicted by the recurrence relation for the region from the long-term earthquake record.

The Queen Charlotte Islands refraction project. Part I. The Queen Charlotte Fault Zone

1988 ◽  
Vol 25 (11) ◽  
pp. 1857-1870 ◽  
Author(s):  
Sonya A. Dehler ◽  
Ron M. Clowes
Keyword(s):  
Fault Zone ◽  
Structural Model ◽  
Seismic Refraction ◽  
Oceanic Lithosphere ◽  
North American Plate ◽  
Ocean Bottom ◽  
Queen Charlotte Islands ◽  
Lower Terrace ◽  
Vertical Fault ◽  
Ocean Bottom Seismographs

The active margin between the continental North American plate and oceanic Pacific plate west of the Queen Charlotte Islands was the site of an extensive onshore–offshore seismic refraction project in 1983. An airgun line shot over two ocean-bottom seismographs (OBS's) and a 32-charge explosion line recorded on the two OBS's and eight land-based seismographs (LBS's) deployed across northern Moresby Island were selected to study the structure of the predominantly transform Queen Charlotte Fault Zone and the associated offshore terrace. Two-dimensional ray tracing and synthetic seismogram modelling produced a pronounced laterally varying velocity structural model showing three major crustal components (oceanic, terrace, and continental) separated by an outer, crustally pervasive fault and active Queen Charlotte Fault, respectively. The 3 km thick block-faulted upper terrace unit, overlain by deformed sediments, is indistinguishable from adjacent oceanic sediments and upper crustal basalts located to the west. The upper part of the 10–17 km thick lower terrace unit has anomalously low velocities relative to the adjacent oceanic and continental crustal units. A high gradient increases terrace velocity rapidly with depth until the contrast becomes negligible at approximately 17 km depth. Changes in depth to Moho beneath the terrace suggest an increase in eastward Moho dip from 2–5 °observed west of the terrace to 19 °below it. Tectonic mechanisms proposed to explain the anomalous terrace structure involve sediment accretion during subduction of oceanic lithosphere, alternating or combined with compressive upthrusting of material along near-vertical fault planes during periods of active transform motion.

Hydrocarbon-bearing characteristics of the SB1 strike-slip fault zone in the north of the Shuntuo Low Uplift, Tarim Basin

2020 ◽  
Vol 27 (1) ◽  
pp. petgeo2019-144
Author(s):  
Ziyi Wang ◽  
Zhiqian Gao ◽  
Tailiang Fan ◽  
Hehang Zhang ◽  
Lixin Qi ◽  
...  
Keyword(s):  
Fault Zone ◽  
Tarim Basin ◽  
Oil And Gas ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Hydrocarbon Exploration ◽  
Phase Iii ◽  
Permeability Barrier ◽  
The North ◽  
Migration Pathways

The SB1 strike-slip fault zone, which developed in the north of the Shuntuo Low Uplift of the Tarim Basin, plays an essential role in reservoir formation and hydrocarbon accumulation in deep Ordovician carbonate rocks. In this research, through the analysis of high-quality 3D seismic volumes, outcrop, drilling and production data, the hydrocarbon-bearing characteristics of the SB1 fault are systematically studied. The SB1 fault developed sequentially in the Paleozoic and formed as a result of a three-fold evolution: Middle Caledonian (phase III), Late Caledonian–Early Hercynian and Middle–Late Hercynian. Multiple fault activities are beneficial to reservoir development and hydrocarbon filling. In the Middle–Lower Ordovician carbonate strata, linear shear structures without deformation segments, pull-apart structure segments and push-up structure segments alternately developed along the SB1 fault. Pull-apart structure segments are the most favourable areas for oil and gas accumulation. The tight fault core in the centre of the strike-slip fault zone is typically a low-permeability barrier, whilst the damage zones on both sides of the fault core are migration pathways and accumulation traps for hydrocarbons, leading to heterogeneity in the reservoirs controlled by the SB1 fault. This study provides a reference for hydrocarbon exploration and development of similar deep-marine carbonate reservoirs controlled by strike-slip faults in the Tarim Basin and similar ancient hydrocarbon-rich basins.

Neotectonics of the SW Marmara region, NW Anatolia, Turkey

2006 ◽  
Vol 143 (2) ◽  
pp. 229-241 ◽  
Author(s):  
ÖMER FEYZI GÜRER ◽  
ERCAN SANGU ◽  
MUZAFFER ÖZBURAN
Keyword(s):  
Fault Zone ◽  
Structural Characteristics ◽  
Strike Slip ◽  
North Anatolian Fault ◽  
Marmara Region ◽  
Field Observations ◽  
Extensional Tectonics ◽  
North Anatolian Fault Zone ◽  
The North ◽  
Differential Movement

This study reports on the geometric and structural characteristics of the North Anatolian Fault Zone in the southwest Marmara region. The geometric and kinematic features of the faults in the region are described, based on field observations. In addition, the Neogene and Quaternary basin fill which occupies large areas in the region has been determined, and the tectonic regimes controlling these basins are explained. The neotectonic regime is also explained considering different deformation phases affecting the region. The N–S extension and E–W strike-slip have affected the region possibly since the latest Pliocene–Quaternary. Field observations show that these extensional tectonics around the south Marmara region are related to right strike-slip on the E–W North Anatolian fault zone and the N–S Aegean extensional system. The faults in this zone trend approximately E–W in the eastern part of the region and NE–SW towards the west of the region, indicating that they accommodate rotation in addition to differential movement between adjacent blocks.

A Miocene submarine volcano at Low Layton, Jamaica

1982 ◽  
Vol 119 (2) ◽  
pp. 193-199 ◽  
Author(s):  
G. Wadge
Keyword(s):  
Fault Zone ◽  
Magnetic Anomalies ◽  
Fault Zones ◽  
Strike Slip ◽  
Fissure Eruption ◽  
Strike Slip Fault ◽  
North Coast ◽  
Alkaline Basalt ◽  
Submarine Volcano ◽  
The North

SummaryA submarine fissure eruption of Upper Miocene age produced a modest volume of alkaline basalt at Low Layton, on the north coast of Jamaica. The eruption occurred in no more than a few hundred metres of water and produced a series of hyaloclastites, pillow breccias and pillow lavas, massive lavas, and dikes with an ENE en échelon structure. The volcano lies on the trend of one of the island's major E–W strike-slip fault zones: the Dunavale Fault Zone. The K–Ar age of the eruption of 9.5 ± 0.5 Ma. B.P. corresponds to an extension of the Mid-Cayman Rise spreading centre inferred from magnetic anomalies and bathymetry of the Cayman Trough to the north and west of Jamaica. The Low Layton eruption was part of the response of the strike-slip fault systems adjacent to this spreading centre during this brief episode of tectonic readjustment.

scholarly journals Termination of a Trench-Linked Strike-Slip Fault Zone in the Sumatra–Java Forearc Basin and Accretionary Wedge Complex

2020 ◽  
Vol 21 (4) ◽  
pp. 177
Author(s):  
Maruf M Mukti ◽  
Ilham Arisbaya ◽  
Haryadi Permana
Keyword(s):  
High Resolution ◽  
Fault Zone ◽  
Large Earthquake ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Accretionary Wedge ◽  
The South ◽  
Forearc Basin ◽  
Pull Apart Basin ◽  
Vertical Fault

This paper presents a review of several published seismic reflection and seismicity data and analyzes of high-resolution bathymetry data to revise the exact location and reveal detail characteristics of a strike-slip fault zone that formed the southernmost segment of the Sumatran Fault (SF). Previous works interpreted this fault segment as a horst structure to the south of a pull-apart basin. We observe a clear linear trace of dissected seafloor parallels to SF in the high-resolution bathymetric map. This structure extends from the south of a pull-apart basin in the northwest to the Sunda accretionary wedge farther southeast. This lineament exhibits a narrow valley and a linear ridge that in the subsurface are interpreted as negative and positive flower structures, respectively. The structure exhibits a vertical fault plane and appears to have deformed the accretionary wedge sediments and basement at depth. A cluster of shallow seismicity is observed along this NW-trending fault zone, indicating the activity of this zone. Here, we proposed this strike-slip fault as the Ujung Kulon Fault that marks the southeasternmost segment of the SF zone. This segment deformed the area of the Sumatra-Java forearc basin and terminated in accretionary wedge near the trench. The accumulated strain within UKF may trigger large earthquake in the future, close to the highly populated areas in the coast of Sumatra and Java.Keywords: Strike-slip fault, Sumatra Fault, Ujung Kulon Fault, segmentation, earthquake.

Exploring for unconventional hydrocarbon plays in the Glyde Basin, Northern Territory, using FALCON® airborne gravity gradiometry (AGG) data

2014 ◽  
Vol 54 (2) ◽  
pp. 519
Author(s):  
Peter Kovac ◽  
Luke Titus ◽  
Carlos Cevallos ◽  
Josh Bluett
Keyword(s):  
Fault Zone ◽  
Volcanic Rocks ◽  
Strike Slip ◽  
Airborne Gravity ◽  
Magnetic Survey ◽  
The North ◽  
Marine Carbonate ◽  
Geological Cross Section ◽  
Hydrothermal Dolomite ◽  
Surface Geology

A FALCON® AGG and magnetic survey in the Glyde Sub-basin aims to define the structural pattern to identify unconventional hydrocarbon plays. The survey area consists of variable thick fluvial and lacustrine to shallow marginal marine carbonate-siliciclastic sequences and lesser volcanic rocks. The dominant tectonic feature identified on the AGG data is the Emu Fault Zone: a major structure of the central-southern part of the McArthur Basin. Seismic and surface geology suggest its overall sub-vertical strike-slip nature with positive flower structure geometry. In the north, a regional size pop-up structure, reverse, transpressional and strike-slip faults, and abundant synclines and anticlines identified in the AGG data indicate sinistral transpression. In the south, a transtensional segment of the Emu Fault Zone formed several regularly oriented, fault controlled depocentres. A geological cross-section across the Glyde Sub-basin supported by gravity modelling indicates a system of inverted transtensional faults. Offsets and bifurcations are common, forming local-scale transtensional or transpressional areas. The relationship between dolomitic carbonaceous siltstone, fault-related hydrothermal dolomite (HTD), and the tectonic pattern strongly suggests that the Emu Fault Zone controlled fluid migration and fault-related HTD deposition. Brecciated HTD reservoirs are best developed where a combination of strike-slip movement and extension allowed dolomitising and porosity-generating fluids to migrate along fracture networks, especially in transtensional pull-apart structures, and along the principal faults bounding elevated parts of the basement. This is consistent with the results of the Glyde–1 ST1 exploration well, which drilled 122 m of gas charged dolomitic breccia.

A microseismicity study of the Queen Charlotte Islands region

1989 ◽  
Vol 26 (12) ◽  
pp. 2556-2566 ◽  
Author(s):  
Joane Bérubé ◽  
Garry C. Rogers ◽  
Robert M. Ellis ◽  
Elizabeth O. Hasselgren
Keyword(s):  
Seismic Events ◽  
Seismic Gap ◽  
Ocean Bottom ◽  
Stress Regime ◽  
Focal Mechanism Solutions ◽  
Thrust Faulting ◽  
Queen Charlotte Islands ◽  
Composite Focal Mechanism ◽  
Predominant Orientation ◽  
Ocean Bottom Seismographs

Nineteen land and three ocean-bottom seismographs were operated in the Queen Charlotte Islands region for periods of up to 9 weeks and 5 days, respectively, during the summer of 1983. Three hundred and seventeen seismic events were detected. One hundred and nine earthquakes ranging in size from magnitude −0.5 to 5.1 were well recorded at three or more stations and could be accurately located. Of these, 84 lie on or close to the Queen Charlotte Fault, most within the rupture zone of the great 1949 earthquake (MS = 8.1). The seismic gap, between the rupture zones of the 1949 event and the 1970 earthquake (MS = 7.4) that occurred just south of the Queen Charlotte Islands, exhibited little activity. Eighteen earthquakes, the largest with ML = 3.8, were located east of the fault on northern Graham Island or in adjacent Hecate Strait. Focal depths were generally less than 20 km, and none could be associated with known faults. Composite focal mechanism solutions were obtained for four suites of earthquakes along the Queen Charlotte Fault and for a group east of the fault zone on northern Graham Island. In all cases the solutions indicate thrust mechanisms with the predominant orientation of pressure axes northeast–southwest. The presence of thrust faulting close to the Queen Charlotte Fault suggests that the microseismicity is not occurring on the main transcurrent fault but on subsidiary faults that are moving due to the regional stress regime. Thrust faulting on northern Graham Island can best be interpreted as reflecting the stress field from a locked Pacific and North American boundary.

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