The Eltanin Fault System ( Eltanin Fracture Zone) is a series of six or seven dextral transform faults that offset the Pacific-Antarctic Ridge, a spreading zone between the Pacific Plate and the Antarctic Plate. The efforts that we made, which are described in Appendix A, resulted in a number of additional solutions, especially for the period 1976-1991 and for Mw 5.4-6.0 (see Fig. Wolfe et al. The centroid epicentre and time did not shift appreciably in these different inversions, nor did the geometry of the moment tensor change appreciably. For example, the caridean shrimp Alvinocaris muricola inhabits cold seeps in both the Gulf of Mexico and the Gulf of Guinea, which clearly suggests a gene flow across the Atlantic, but the amount of data is very limited and dispersal pathways are not fully understood. (2005). 1975; Lonsdale 1994), which were named for M. Tharp, B. Heezen and C. Hollister (Fig.
Major differences in seismic coupling along strike are not in accord with common thermal models of plate cooling but instead are attributed to varying degrees of metamorphism, rock type and effective normal stress and possibly to the presence of short intratransform spreading centres. . . Forsyth
Exploring Data Coaching Activity: Longshore C, SmartFigure: Geostrophic current and western. Ships have surveyed the active parts of three Eltanin transforms infrequently since they straddle the pole of inaccessibility' at the farthest point on the Earth from inhabited land (Lonsdale 1994). (1981), Arvidsson & Ekstrm (1998) and Ekstrm et al. The average of the three intervals since 1967 is 12.8 yr with a COV of 0.36. The isobaths are drawn at 500 m intervals between 1900 and 3400 m, from the dataset of Smith and Sandwell (1995). Fielding
A.M.
The two largest (Mw 6.7 and 5.9) occurred well to the north of the transform in 2001 and 2007. Series of faults that offset the Pacific-Antarctic Ridge, "Seismicity and Aseismic Slip Along the Eltanin Fracture Zone", "The Pacififi c-Antarctic Ridge between 4115'S and 5245'S: Survey and sampling during the PACANTARCTIC 2 cruise", "Earthquakes along Eltanin transform system, SE Pacific Ocean: fault segments characterized by strong and poor seismic coupling and implications for long-term earthquake prediction", https://en.wikipedia.org/w/index.php?title=Eltanin_Fault_System&oldid=1068451688, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 28 January 2022, at 13:46. The three sets of large events have a repeat time of 13 yr and a COV of 0.13. side (rather than on top of or away from one another.) 4814 km S of Papeete, French Polynesia / pop: 26,357 / local time: 08:09:44.3 2016-08-18, Distances: 3385 km SE of Wellington, New Zealand / pop: 381,900 / local time: 14:34:59.2 2016-05-03 Johanson
The random variations can be considered a consequence of the complicated trade-offs that occur when noisy data are fit with synthetic seismograms that do not capture the full complexity of wave propagation in the Earth. Swarms of hydrothermal shrimps reminiscent of those found from northern MAR vent-sites have been found on the northern part of the southern MAR. Distances in kilometres same as in Fig. 1997, 2005). The Eltanin Fault System (Eltanin Fracture Zone) is a series of six or seven dextral transform faults that offset the Pacific-Antarctic Ridge, a spreading zone between the Pacific Plate and the Antarctic Plate.The affected zone of the Pacific-Antarctic Ridge is about 800 km long, between 56 S, 145 W and 54.5 S, 118.5 W, southwest of Easter Island, and about as far as one can get from . North of and parallel to the fracture zone is a transverse ridge which is particularly prominent over hundreds of kilometres east and west of the MAB of the South Atlantic. Dziak
The normal-faulting event of 2001 August 6 is larger than that of any of the strike-slip events along the three Eltanin transforms. The flow of NADW through the Romanche and Chain Fracture Zones may serve as a conduit for larval transport from the western North Atlantic to the eastern South Atlantic. 4). How are fracture zones like the Eltanin created? 7, several of which are aftershocks and foreshocks, are considered to be noise in ascertaining the quasi-periodic behaviour of the larger shocks. The excitation of the long-period waveforms used in the CMT analysis does not vary rapidly as a function of source depth for shallow-focus earthquakes.
New Mw corresponds to seismic moment magnitude recomputed for this study. Atwater
The experiment suggests that when the CMT depth is larger than the true depth, the estimated Mo is too high by a small amount. florida a jurassic transform plate boundary. Where is and what is Eltanin Transform Fault and Fracture Zone? The feature was then named the Eltanin fracture zone. Also, there was no discontinuous change in the calculated Mo when the CMT was evaluated above the Moho (which in PREM is at 24.4 km) or below it. 7 includes an earthquake on 1981 June 20 of Mw 5.94, which was located just to the east of the others at a time when relatively few stations were available for calculating a CMT location. Solomon
G.
Available long-period data for events along the three transforms increased from about 15 to 100 global stations as illustrated in Fig. K.
Only the Heezen transform has been surveyed by swath mapping (Lonsdale 1994). When Sykes showed his results to M. Ewing, the latter arranged with NSF (US National Science Foundation) for the Research Vessel Eltanin to map the region. A new analysis of plate cooling models indicates that the properties of oceanic lithosphere may need to be reevaluated, or that additional phenomena beyond the conditions of simple mineral physics plate models are important. One 30-42-km-long segment of the Heezen transform that appears to be an isolated well-coupled asperity has ruptured in eight earthquakes of Mw 5.9-6.1 quasi-periodically with a coefficient of variation of 0.26 every 4.0 1.0 yr. Other well-coupled fault segments, which were sites with earthquakes up to Mw 6.39 and fewer events since 1976, have average repeat times of about 7-24 yr.
4. Approximate slopes are denoted by dashed lines. VanDeMark
C.
Their length, relative simplicity, 80 mm yr-1, long-term slip rate and the lack of known shocks of Mw > 7 make them a good laboratory for studying quasi-periodic recurrence of earthquakes on a timescale of years to a few decades. McGuire (2008) also found that 1-d aftershock zones extended 30-50 km along strike for Mw~ 6 main shocks for transforms of the East Pacific Rise near the equator. Table S1 in the Supporting Information lists the formal uncertainties of the revised centroid locations. Topographic Map of Eltanin Fracture Zone. Nakata
The island is very long and narrow. In addition those three oceanic transforms are not as multibranched as many transform zones on continents. We find one segment of the Heezen transform has ruptured quasi-periodically since 1976 in eight shocks of Mw 5.9-6.1 with an average repeat time of 4 yr. We recomputed centroid moment tensor (CMT) solutions for 190 earthquakes along and close to the three transforms of the Eltanin system from 1976 to 2010. For LNADW and AABW, the Romanche and Chain Fracture Zones (just south of the equator) are the only deep passages in the MAR where interbasin exchange is possible. Two 20-km segments of the Hollister transform (Figs 3 and 6) are the sites of several earthquakes of Mw= 5.9 whereas only single shocks of that size are found along its western half. Incidences of 20,538 trochanteric and femoral neck fractures in adult Swedish men and women, from a computerized medical information register for all hosp Shimazaki
Atwater
They differ in that hypocentres derived using body waves give the location of rupture initiation whereas CMT solutions give centroid locations and origin times. Subsequent locations of earthquakes and mapping of bathymetry and magnetic anomalies showed that the Eltanin zone consisted of three en echelon transforms (Molnar et al. Distances in kilometres same as in Fig. Where is and what is Eltanin Transform Fault and Fracture Zone. Eltanin Fracture Zone System is located in the Undersea Features Area of the Country of Undersea Features. Lonsdale
The boat was returning to France after spending a few months on a scientific mission near Cape Horn as part of the first International Polar Year. What did the Nazis begin using gas chambers instead of mobile killing units and shooting squads after a while? The presence of short intratransform spreading segments is one factor but others may be differences in hydrothermal alteration and rock type, the sizes of asperities and varying normal stresses and fluid pressures that may place some segments in the velocity strengthening regime and others in the velocity weakening regime. Sykes
11 between Mw 5.4 and 6.0 for events from 1991 to 2010. [3], Series of faults that offset the Pacific-Antarctic Ridge. Unfortunately, the computed depths of earthquakes along the three Eltanin transforms are not accurate enough to ascertain centroid depths or the downdip width of seismic faulting at the several to 20 km level. Dotted lines denote approximate locations of ridge segments. Eltanin Fracture Zone System: IHO-IOC GEBCO Gazetteer of Undersea Feature Names : English: Eltanin Fracture Zone: US BGN Advisory Committee on Undersea Features (ACUF) PlaceType: Fracture Zone : Latitude: 54 8' 16.8" S (-54.137999) Longitude: 127 32' 7.3" W (-127.53537) Min. Sunrise: 06:37AM; Sunset: 05:22PM; Day length: 10h 45m; The local time in Stockholm County is currently the same as the solar time. Listen to the audio pronunciation of Eltanin Fracture Zone on pronouncekiwi Note exaggerated scale in transform-perpendicular direction. (1993) and Lonsdale (1994) describe three short spreading centres with a total length of about 6 km along the seismically quiet part of the Heezen transform between 125.5 and 126 W (Fig. Events in 2010 were determined in the same manner and are listed in the catalogue of the GCMT project at http://www.globalcmt.org. Hirth
Their surface wave magnitudes, Ms, for events before 1969 along the Eltanin system were determined typically from one to a few stations. C.J. Deep water flow through the trench is from west to east with a rate of 3.6 Sverdrups (million m/s) of 1.57C (34.83F) water. P.
It is one the the major earthquake zones in Watts
The Eltanin Transform Fault and Fracture Zone is a series of six or seven dextral transform faults along ~800 km of the Pacific-Antarctic Ridge that offset it ~1600 km. Wilson (1965) utilized the observation that earthquakes along the Eltanin fracture zone were confined to the zone between two offset ridge crests in formulating his hypothesis of transform faulting. The Eltanin Fault System (Eltanin Fracture Zone) is a series of six or seven dextral transform faults that offset the Pacific-Antarctic Ridge, a spreading zone between the Pacific Plate and the Antarctic Plate.The affected zone of the Pacific-Antarctic Ridge is about 800 km long, between 56 S, 145 W and 54.5 S, 118.5 W, southwest of Easter Island, and about as far as one can get from . FRACTURE ZONE. The seismic history of the Eltanin Fracture Zone on the Pacific-Antarctic Ridge for the years 1920-1981 shows that the seismic slip accumulated during this recording interval accounts for only a small fraction (less than 10%) of the amount of slip predicted by kinematic models of plate motion. The eastern part of the transverse ridge, however, consists of a thick sequence of stratified material called the Romanche Sedimentary Sequence (RSS). Most prominent is an asymmetric transverse ridge, at which abyssal hills adjacent to the fault zone have been . The smaller events in Fig. VanDeMark (2006) analysed the relative locations of earthquakes of moderate magnitude along oceanic transform faults with a double-difference method using Rayleigh waves of periods between 30 and 80 s. He used 92 events along the Eltanin transform faults from 1980 to early 2006, about half of the number we analysed. 4706 km S of Papeete, French Polynesia / pop: 26,400 / local time: 01:42:15.1 2017-06-15 The relationship between the two events that occurred on the same day with computed CMTs only 5 km apart is unknown. N.N. . The solutions, additional methodology and other pertinent data are described more fully in Appendix A and the Supporting Information. 'dextrally' (also known as right-laterally) which means if you Subsequent locations of earthquakes and mapping of bathymetry and magnetic anomalies showed that the Eltanin zone consisted of three en echelon transforms (Molnar et al. Blue symbols indicate four normal faulting mechanisms and their T-(extensional) axes. F.
Shen
. Fracture Zone. The RSS includes pelagic material from the early Cretaceous (140 Ma) which, coupled with the thickness of the sequence, does not fit with the normal scenario for the opening of the South Atlantic around the Aptian-Albian (125100 Ma). 2). Symbols, axes and origin of coordinates same as Fig. Chou
If the anomalous trend is real, having one group of events (east or west) off the primary transform then almost becomes a necessary interpretation. R.C. Duncan
R.
His relocations are shown in Figs 4-6 in green. 7, however, since it is located just to the east of other large shocks along the Heezen transform. . Fig. Dziewonski
Ekstram
of fracture zones in the southern oceans by mavis lynn driscoll b.a., university of california at berkeley, 1981 submitted in partial fulfillment of the requirements for the degree of doctor of philosophy at the massachusetts institute of technology and the woods hole oceanographic institution june 1987 Bohnenstiehl
Although magmatism was more or less continuous on the ridge during 28-60 Ma, it probably occurred on crust . Fishing enthusiasts interested in fishing near or at Eltanin Fracture Zone System should print out the Google map and take it with them on their . Bivalve communities have been reported around vents further south. D.W.
Abstract.
We have combined shipboard and Seasat altimeter derived data in an intergrated geological and geophysical study of the Louisville Ridge; a 3500kmlong seamount chain extending from the Tonga trench to the Eltanin Fracture Zone. Challenger Fracture Zone. How are fracture zones like the Eltanin created? That view was strengthen when Menard reviewed the manuscript and provided an unpublished bathymetric map that included more data in the far southeast Pacific. Wolfe et al. Their surface wave magnitudes, Ms, are plotted.
4. The zone is in the South Pacific, southwest of Easter Island, between 56 S, 145 W and 54.5 S, 118.5 W. The Dead Sea fault zone is located on a Transform boundary. The plate boundary is about 1,200 kilometers long along the Antarctic Bottom Water (AABW) flows below the LNADW and reaches down to the seafloor. The summit of the transverse ridge is capped by Miocene shallow water limestones that reached above sea level 20 Ma before subsiding abnormally fast. 9 for two sequences of earthquakes along the Tharp transform. The morphology of the Atlantis Fracture Zone is typical of that of slow-slipping transforms. Watts et al. Dziewonski
How do you say Eltanin Fracture Zone? The transform valley is 15-20 km wide and 2-4 km deep. Hence, we cannot distinguish between those two models. Four of them have T-axes nearly perpendicular to those transforms while the smallest of Mw 5.3 in 1982 is oriented about 45 to the Tharp. transform plate boundaries learning geology. E.A. Nevertheless, modelling body waves is difficult for strike-slip earthquakes along the Eltanin transforms because their amplitudes are small at recording stations that necessarily are at very large distances. The Eltanin Fault System (Eltanin Fracture Zone) is a series of six or seven dextral transform faults that offset the Pacific-Antarctic Ridge, a spreading zone between the Pacific Plate and the Antarctic Plate.The affected zone of the Pacific-Antarctic Ridge is about 800 km long, between 56 S, 145 W and 54.5 S, 118.5 W, southwest of Easter Island, and about as far as one can get from . Gregg
Previously, some epicentral locations in that area were uncertain by as much as 500 km. The synthetic waveforms used in the CMT inversion are corrected for lateral heterogeneity using the whole-mantle model of Dziewonski & Woodward (1992) for the body waves and long-period mantle waves, and the phase-velocity maps of Ekstrm et al. Earthquakes of Mw 6.2-6.4 have occurred repeatedly (Fig. Some other fault segments with larger events rupture with less certain repeat times of 7-24 yr. Other segments are poorly coupled for shocks of Mw > 5.4 and perhaps smaller. Other short spreading centres may exist along the Tharp and other parts of the Heezen transforms. The inversion procedure follows the method of Ekstrm (1989) and leads to estimates of the earthquake focal mechanism, source-time function and point-source depth that are consistent with both the P-wave data and the CMT results. On this Wikipedia the language links are at the top of the page across from the article title. In discriminating the signals of earthquakes from those of underground nuclear explosions low excitation of Rayleigh waves in the narrow period band used for determining Ms may result in a few earthquakes appearing to be explosions. Fig. The trench has been formed by the actions of the Romanche Fracture Zone, a portion of which is an active transform boundary offsetting sections of the Mid-Atlantic Ridge. Cumulative moment release is shown in Fig.
In relocating earthquakes along the East Pacific Rise and Pacific-Antarctic Ridge, Sykes (1963) found that the pattern of epicentres was offset about 1000 km near 55 S. Forsyth
Use the facts stated above when they apply. Computed CMT depths in Table S1 in the Supporting Information range from 12 to 26 km, with 12 being the smallest constrained depth. Menard
"zone" in Chinese : n. 1. () 2. 3. . Fig. . 4065 km S of Avarua, Cook Islands / pop: 13,373 / local time: 16:34:59.2 2016-05-02 For the larger and more complex 2001 earthquake the rupture initiation depth is 8.9 km, and the centroid depth, taking into account the propagation of the point source in the direction of the directivity vector, is approximately 11 km, about 7 km below the ocean floor. Lat: H.W. R.E. (2007) and others modelled temperatures in the vicinity of oceanic transform faults at fast moving plate boundaries that differ from those for the earlier simple plate cooling models. The remarkable quasi-repeatability of events of Mw > 5.9 may be attributed to the isolation of an asperity, that is, a single resisting fault segment that ruptures mainly or solely in earthquakes. S1 in the Supporting Information shows the revised CMT solutions for 186 earthquakes from 1976 to 2009 on the left and those in the online catalogue on the right. [1] The two major faults in the Eltanin Fracture Zone are the Heezen Fault and the Tharp Fault. Sykes & Menke (2006) calculated maximum-likelihood estimates of COV that were 0.3 or smaller for a number of large-to-great earthquakes that ruptured nearly the same segments of strike-slip and subduction zone faults. This is a consequence of the continuity of displacement eigenfunctions for surface waves across discontinuities, and the dependence of the excitation on these displacements. 2). Eltanin has a maritime climate in the transition region between the tundra and subarctic zones (Kppen classification) which is characterised by . Our calculations of moment magnitude Mw are compared with determinations of the short-period magnitude mb in Fig.
P.
Undersea Features Fishing & Outdoor Fracture Zone Maps: Undersea Features is home to a total of 187 Fracture Zone(s), listed below. [6] The central part of the Tharp transform near -350 km in Fig. He concluded that a major fracture zone intersected the mid-oceanic ridge at that location, much like those mapped by Menard (1960) farther north.
T.F. The Fracture Zone is located at the latitude and longitude coordinates of -54 and -130. Which letter(s) is/are pointing to an inactive fracture zone? Thus, the use of the CMT methodology insured more complete coverage of earthquakes in this very remote area of the Earth. Red and green symbols denote strike-slip faulting. The Atlantis Fracture Zone (30 N) is one of the smallest transform faults along the Mid-Atlantic Ridge with a spatial offset of 70 km and an age offset of ~ 6 Ma. According to the normal scenario for the opening of the South Atlantic, it is spreading at a rate of 1.75cm/year (0.69in/year) and began forming about 50 Ma. SEANOE. A break in the smooth trend of the ridge at latitude 37.5S has been recognized in both bathymetric and altimetric data. Dziewonski
Their poorly determined repeat times range from 13 to 24 yr. For the four seismically active fault segments in Table 1 we obtain similar downdip widths of seismic faulting of about 5 km assuming coupling at the full plate rate. T.
Ryan
The segment between -575 and -580 km was the site of only two large earthquakes, Mw 6.22 and 6.24. C2 shows that Mw is similar to Ms at larger magnitudes but is 0.40.9 units larger at Mw 5.4. Stewart
Menard
J.T. H.W. How are fracture zones like the Eltanin created? Distances in kilometres same as in Fig. With that assumption we obtain downdip widths of about 5 km for four segments of the Heezen, Tharp and Hollister transforms. What do the parents perceive as their role to the Day Care worker? The absence of known earthquakes on the three transforms beyond their bounding ridge crests and the spacing of magnetic anomalies, however, indicate that the Pacific and Antarctic plates are intact today beyond the active parts of those transforms and that the lengths of the transforms are not continuing to grow. Cumulative seismic moment release 1971 to 2010 along two segments of Tharp transform as indicated in Fig. A.B. Boettcher
Figs 5 and 6 show five other normal-faulting mechanisms adjacent to but not on the Tharp and Hollister transforms. . Our knowledge of the Eltanin system is limited by the relatively high magnitude of completeness of events, Mw 5.4, and the paucity of aftershocks and forerunning events. Of the 84 earthquakes from 1976 to 1989, we rejected seven CMT solutions. 4 are more tightly clustered in map view. 3315km (2060mi) WSW of Punta Arenas, Chile 1). These segments contain fewer events of Mw > 5.9 than that in Fig. J.
G.
The maximum size of earthquakes along fast spreading ridges themselves is not greater than magnitude 3 (McGuire 2008; M. Tolstoy, personal communication, 2010). Similarly, the series between 95 and 121 km (blue in Fig. Hence, we suspect that the events at the western end of the Tharp transform are anomalous in some sense. 7; several were the sites of two or three earthquakes of Mw > 6.15. The T-axis of a normal-faulting event in that area of Mw 5.4 in 1978 is inclined about 45 to the transform (Fig. (2005), McGuire (2008) and Boettcher & McGuire (2009) find that some fault segments are characterized by a predominance of aseismic slip while others are fully coupled. The most recent data show, for example, that the Eltanin fracture zone system in the South Pacific is much longer than previously thought, according to Marsh. (1993) and Abercrombie & Ekstrm (2001) clearly include the uppermost oceanic mantle for earthquakes along three slower moving transform faults in the Equatorial Atlantic. what makes muscle tissue different from other tissues? The Eltanin Fault System (Eltanin Fracture Zone) is a series of six or seven dextral transform faults that offset the Pacific-Antarctic Ridge, a spreading zone between the Pacific Plate and the Antarctic Plate. Molnar
4. D.V. 4. S. Carbotte kindly computed the bathymetric map in Fig. The zone is in the South . et al. P.M.
Sunrise, sunset, day length and solar time for Stockholm County. This partitioning of slip likely results from changes during the last few million years in the Euler pole for relative motion between the Antarctic and Pacific plates. 4. "eltanin" in Chinese : "fracture zone" in Chinese : ; ; ; ; ; . To address part of this question, we performed the following experiment. We note that our revised catalogue with its additions of more solutions, especially of Mw 5.5-6.0, is more complete than the existing CMT catalogue. They conclude that the Blanco and Gofar transforms, which were the target of their study, appear to be comprised of multiple patches on a single fault segment that repeatedly fail in earthquakes that rupture each of those patches. 11 displays the log of the cumulative number of events per 20 yr as a function of decreasing Mw for the periods 1976-1990 and 1991-2010. https://earthquake.usgs.gov/earthquakes/eventpage/us20009msm#executive, http://www.emsc-csem.org/Earthquake/earthquake.php?id=504225, http://earthquake.usgs.gov/earthquakes/eventpage/us100049ce#general_summary, Follow Earth Extremities on WordPress.com, MAGNITUDE6.9KERMADEC ISLANDS, NEWZEALAND, MAGNITUDE5.6SOUTHERN MID-ATLANTIC RIDGE, MAGNITUDE5.6EAST OF SOUTH SANDWICHISLANDS, MAGNITUDE6.9KERMADEC ISLANDS, NEW ZEALAND. The San Andreas fault is part of a fault zone known as a transform
Ekstram
Mw is systematically higher than mb for strike-slip events along the three transforms, on average about 0.5 units.
S. Carbotte (written communication, 2011 July 22) notes that the concentration of earthquakes at the eastern end of the Heezen transform corresponds with the region where the inside Corner Rift' of Lonsdale (1994) is found to the north. . The San Andreas Fault zone of western North America. A major purpose of our work is to examine the degree of repeatability (or lack thereof) of major earthquakes along various segments of the three Eltanin transforms. Bar at upper right on map shows water depths in metres. [1] The two major faults in the Eltanin Fracture Zone are the Heezen Fault and the Tharp Fault. Abercrombie
4. The Romanche and Chain Fracture Zones creates a huge gap in the MAR and can act as a "Subsea Berlin Wall" segregating the North Atlantic communities from those in other oceans. ISC located an earthquake along that segment of Ms 6.1 on 1967 September 9.