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. Yellow squares show stations for event of 2007 March 31 of Mw= 6.2; the red hexagons show stations for earthquake of 1983 July 5 of Mw= 6.2. In addition those three oceanic transforms are not as multibranched as many transform zones on continents. 7; several were the sites of two or three earthquakes of Mw > 6.15. Numbers for 15 yr period 1976-1990 were multiplied by 20/15. NASA Technical Reports Server (NTRS) Kyte, Frank T.; Gersonde, Rainer; Kuhn, Gerhard. a generally flat zone extending from the shore to the shelf break continental margin shallow-water areas close to continent abyssal plain flat depositional surfaces that cover extensive portions of the deep-ocean basins The method that used most frequently to investigate sediment and rock layers of the sea floor is: Rupture of two or more nearby asperities in shocks as large as Mw 6.4 can occur but is rare as ascertained from the steep slope of the frequency-magnitude relationship in Fig. Instead, we have chosen not to use models of the depth of seismic faulting in estimating coupling but to calculate downdip width from a segments length along strike, moment release rate and relative plate rate assuming' full seismic coupling.
CHALLENGER FRACTURE ZONE. S1 in the Supporting Information). W.
Fielding
8, interaction between the two may well occur. They are the scars on the seafloor basalt that are created by offsets in the mid-ocean ridge. The presence of large events just to its west and the variety of Mws, however, suggest that it does not always rupture as a single asperity. What did the Nazis begin using gas chambers instead of mobile killing units and shooting squads after a while? Fig. Which two plates create the Eltanin Fracture Zone? 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. In the basin on the eastern side of the MAR the Walvis Ridge blocks the northward passage. . What is the reflection of the story of princess urduja? Y.
The mechanism in the GCMT catalogue indicates normal faulting, while the reanalysis resulted in a strike-slip mechanism. At faster separating parts of the Pacific-Antarctic boundary, and on most of the rest of the EPR, fracture zone structure is mainly inherited from the variable arrangement of volcanic ridges and tectonic uplifts at the risecrest intersections, rather than from structures formed at the transform valley. . 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. Langenhorst
2006). (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. It is one the the major earthquake zones in 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. If so, their repeat time was about 16 yr but is based on only three events. They find that aftershock zones of nearby pairs of moderate-size earthquakes along fast-moving transforms were separated by small spreading centres. This bias suggests that the models used for CMT and ISC locations are not slow enough to the north and northeast along the East Pacific Rise. The CMT centroid depths for events along the Eltanin system are not accurate enough to define the depths or range of seismic faulting at the level of several to 20 km. Enter the email address you signed up with and we'll email you a reset link. A.M.
Watts et al.
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. Archived seismicity, satellite altimetry, and older geophysical traverses extend these descriptions . 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. Our locations and those of the ISC based on body waves are located systematically about 25 km south of the transforms as mapped in Fig. However, a major offset developed on this transform between 60 and 80 Ma, prior to the oldest dated rocks from the ridge. The centroids of events of larger Mw are found at least 35 km eastwards along the Heezen transform and those to its west are relatively small. The segment of the Heezen transform between 29 and 71 km (Fig. The present application of this method points to a recent change in Pacific plate motion, and. He concluded that a major fracture zone intersected the mid-oceanic ridge at that location, much like those mapped by Menard (1960) farther north. Lonsdale (1994) concludes that a zone of extension north of the Heezen transform developed following a Pliocene change in relative plate motion. Their average repeat time is 7.1 yr and their COV is 0.28. , and M is in kg. Clearly, a gradient in the maximum size of earthquakes and seismic coupling occurs between the eastern and western ends of the Heezen transform. Lat: Thus, the use of the CMT methodology insured more complete coverage of earthquakes in this very remote area of the Earth. Lamont-Doherty Earth Observatory Contribution 7505. We determined a CMT solution for it using seven digital stations and obtained a Mw of 6.1, a strike-slip mechanism and a location (red triangle) about 20 km west of the group indicated in Fig. The Polar and Subantarctic Fronts are observed to pass along the Udinstev Fracture Zone 3 as the jets in the flow are steered by the topography (e.g., Moore et al. Fig. . Okal
That segment may well not be a single isolated an asperity as that in Fig. M.S. (2005). 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. This is in accord with the findings of Stewart & Okal (1983) that the Eltanin system has not broken in great events since 1920 and is unlikely to do so. Except for an event in 1975 we did not reanalyse long-period data for earthquakes prior to 1976, but we utilize the approximate locations of some of those larger events in estimating repeat times. Mw determined in this study compared with the surface wave magnitude Ms as computed by either ISC or PDE for periods between about 17 and 22 s. Mw is determined at longer periods. In those circumstances the use of longer period Rayleigh and Love waves, as in the CMT methodology, can lead to those events being identified confidently as earthquakes.
The smaller events in Fig. Dziewonski
Fox
The western part of the transverse ridge consists of fragments of uplifted oceanic crust and upper mantle. Listen to the audio pronunciation of Eltanin Fracture Zone on pronouncekiwi which two plates create the eltanin fracture zone quizlet; Well Inspection using ROV at Kondashetti Halli, Bangalore D.W.
Lonsdale (1994) mapped a small nearby series of short spreading centres along the Heezen transform, one along the Raitt transform farther north and the Udintsev farther south. The segment of the Heezen from 179 to 200 km has the next smallest T, 7.1 yr, Mw 5.89-6.5 and six events. (1993) find that a 10 clockwise rotation of magnetic anomalies north of the Heezen transform occurred within the last 4 Ma, which would put it in extension. The affected zone of the Pacific-Antarctic Ridge is about 800kmlong, between 56 S, 145 W and 54.5 S, 118.5 W,[1] southwest of Easter Island, and about as far as one can get from land on planet Earth (4852.6S 12323.6W). A.M.
Enter your email address to follow this blog and receive notifications of new posts by email. Seabeam and SeaMARC II swath-mapping surveys, with ancillary magnetic and gravity profiling, describe the fast-slipping (84-86 mm year1) 380 km-long Heezen transform (56 S) and the 145 km-long Raitt transform (54 S), together with the youngest parts of their rise-flank fracture zones. 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. C1. The isobaths are drawn at 500 m intervals between 1900 and 3400 m, from the dataset of Smith and Sandwell (1995). (1993) obtained two normal-faulting mechanisms and computed depths of faulting from waveform matching.
Broader Terms: East Pacific Pacific Ocean South Pacific Southeast Pacific Similarly, the series between 95 and 121 km (blue in Fig. 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. P.
plates. The smooth trend of the ridge is NNW-SSE with a trend break at about 37.8S. Boettcher
This transform migration was preceded by a process 2517 Ma during which the Miocene shallow-water platform mentioned above reached sea level as the transverse ridge was first uplifted, then deformed, and finally buried under the sea. Antarctic Bottom Water (AABW) flows below the LNADW and reaches down to the seafloor. J.S. The red series in Fig. Those estimates are smaller than those for oceanic transforms at much slower moving plate boundaries, which is in accord with the notion, which we accept, that temperatures are higher at a given depth for fast moving plate boundaries. (1993) attribute it to one of those small spreading centres. 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. 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. Although Abercrombie
C.J.
I.A. "zone of fracture" in Chinese : , ; ; ,; ; "fracture system" in Chinese : ; "amsterdam fracture zone" in Chinese : 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. We show events characterized by a predominance of strike-slip faulting that we located since 1976 in red along with the few earthquakes in blue that involved a predominance of normal faulting. 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). The fracture along blocks of crust (tectonic plates) is called a Ekstram
Eltanin Fracture Zone on the Elevation Map. The horizontal axis is parallel to computed transform directions; the vertical is perpendicular to it. Mammericks
It is formed by a transform boundary. . H.W. (1993) and Lonsdale (1994) concluded that the event of 1984 August 16 (Mw 5.3) was located along a bathymetric trough to the north of the Heezen transform. 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. Others related faults include the Vacquier Transform Fault, the Menard Transform Fault, and the Udintsev Fault.[3]. 4706 km S of Papeete, French Polynesia / pop: 26,400 / local time: 01:42:15.1 2017-06-15 Systematic deviations can occur when the Earth structure in the source area deviates significantly from the structure assumed in the calculation of synthetic seismograms, that is, from PREM (Dziewonski & Anderson 1981). Show that the equation is dimensionally correct. Solid line indicates Mw=mb. "eltanin" in Chinese : "fracture zone" in Chinese : ; ; ; ; ; . "zone" in Chinese : n. 1. () 2. 3. . 3). T.
where is and what is eltanin transform fault and fracture. Regardless of the cause of the deviation of the centroid depth from the true depth, the question arises whether an incorrect centroid depth can cause the scalar seismic moment, Mo, estimate to differ from the true moment in a systematic way. Hirth
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. We determined a few CMT mechanisms for which PDE or ISC did not compute hypocentres, for which we relied on detections and locations based on intermediate-period surface waves (Ekstram 2006). Our findings are in contrast to the widely stated notion that oceanic transform faults, especially those at fast spreading plate boundaries, are poorly coupled with perhaps the presence of occasional stuck patches or asperities. Solid line indicates Mw=Ms. GE was partially supported by NSF grant EAR-09-24694. Exploring Data Coaching Activity: Longshore C, SmartFigure: Geostrophic current and western. The four estimates of W in Table 1 range from 3.9 to 6.0 km. DeMets
We propose that the remainder of the plate motion . We chose one of the Eltanin earthquake of (2009 May 7, Mw= 5.6) for which the CMT centroid depth is 25.7 km, and calculated the CMT at various fixed depths, inverting as usual for all the other parameters. Ekstram
Chou
L.R. The point source depth of 10.4 km places the 2007 earthquake 6-7 km below the ocean floor.
Okal & Langenhorst (2000) relocated a number of earthquakes along the three transforms using short-period body waves. These are very small, typically 3-15 km for the earliest events and 1-2 km for earthquakes since 2000. Phipps Morgan
Their 1000 km length is greater than that of any other oceanic transforms at fast-spreading plate boundaries. The waveforms were edited using the standard Global CMT (GCMT) automated waveform editor, and inverted using the standard Global CMT computer codes using corrections for 3-D earth structure in the calculation of synthetic seismograms (Ekstram . Our determinations of Mw typically use observations at more stations than those of Ms. Those for Mw also use Love and Rayleigh waves. Use the facts stated above when they apply. These depths are similar to those determined by Wolfe et al. To address part of this question, we performed the following experiment. Lynn R. Sykes, Gran Ekstrm, Earthquakes along Eltanin transform system, SE Pacific Ocean: fault segments characterized by strong and poor seismic coupling and implications for long-term earthquake prediction, Geophysical Journal International, Volume 188, Issue 2, February 2012, Pages 421434, https://doi.org/10.1111/j.1365-246X.2011.05284.x. The fast rate of plate motion, maximum size of events and relatively short repeat times make these fault segments a good laboratory for research on quasi-periodic behaviour and earthquake prediction. We obtained a CMT solution for an additional earthquake of Mw 6.15 in 1979. The earthquakes were analysed using the standard Global CMT (GCMT) algorithm as described in Dziewonski et al. It and some other segments of the three Eltanin transforms appear to be well coupled seismically. A Seabeam reconnaissance of the 400 km-long fast-slipping (88 mm yr-1) Heezen transform fault zone and the 55 km-long spreading center that links it to Tharp transform defined and bathymetrically described several types of ridges built by tectonic uplift and volcanic construction. Swarms of hydrothermal shrimps reminiscent of those found from northern MAR vent-sites have been found on the northern part of the southern MAR. The few involving normal faulting are located up to 40 km on either side of the transforms and involve extension nearly normal to the transforms. Wolfe et al. The 40Ar39Ar dating of rocks dredged . His events along what we identify as a well-coupled zone between 29 and 59 km in Fig. Lonsdale (1994) states My interpretation is that mechanical coupling across the transform valley allows eastward drag by the old thick Antarctic lithosphere to impede the westward movement away from the rise crest of a 20-30-km-wide adjacent strip of thin, newly accreted Pacific lithosphere'. 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 Woodhouse
The segment near the eastern end of the Heezen transform between 179 and 200 km (Fig. 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. 5) are characterized by shocks of Mw= 5.9 but about half of its length is not. What is the labour of cable stayed bridges? The island is very long and narrow. Eltanin Fracture Zone.
What causes the formation of offsets in the mid-ocean ridge system? What is error code E01-5 on Toyota forklift. Formed around Antarctica, the AABW is cold, has low salinity, and high silicate concentration. (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. Earth Extremities I cover many earth extremities ranging from Earthquakes, Quake Swarms, Volcanic Activity/Eruptions, CME's - Coronal Mass Ejections, Solar Flares, Geomagnetic Storms, Magnetosphere Pressure plus other solar related radiation pulses, Asteroid/Meteorite Threats, Solar . For full access to this pdf, sign in to an existing account, or purchase an annual subscription. The normal-faulting event of 2001 August 6 is larger than that of any of the strike-slip events along the three Eltanin transforms. R.
Extending the work of Stewart & Okal (1983), they again emphasized the dominance of aseismic slip. . The time-predictable model (not shown), in which the time to the next earthquake is proportional to the size of the preceding large event, also fits the data, though slightly less well. Distances in kilometres same as in Fig. - 4:5, using intermediate-period surface waves, Thermal structure of oceanic transform faults, Scaling relations for seismic cycles on mid-ocean ridge transform faults, Aftershock sequences in the mid-ocean ridge environment: an analysis using hydroacoustic data, Determination of earthquake source parameters from waveform data for studies of global and regional seismicity, A very broad band inversion method for the recovery of earthquake source parameters, Global detection and location of seismic sources using surface waves, Measurements and global models of surface wave propagation, Global seismicity of 2003: centroid-moment-tensor solutions for 1087 earthquakes, Source of oceanic magnetic anomalies and geomagnetic polarity time scale, Spreading rate dependence of gravity anomalies along oceanic transform faults, Co-seismic and postseismic slip of the 2004 Parkfield earthquake from space-geodetic data, Structural geomorphology of the Eltanin fault system and adjacent transform faults of the Pacific-Antarctic plate boundary, Seismic cycles and earthquake predictability on east Pacific rise transform faults, Foreshock sequences and short-term earthquake predictability on east Pacific rise transform faults, Magnetic anomalies, bathymetry and the tectonic evolution of the South Pacific since the Late Cretaceous, Three-dimensional flow and temperature perturbations due to a transform offset, Seismic properties of the Eltanin transform system, South Pacific, Global multi-resolution topography synthesis, Multiple, closely spaced transform faults in fast-slipping fracture zones, The effects of temperature and pressure-dependent viscosity on three-dimensional passive flow of the mantle beneath a ridge-transform system, Time-predictable recurrence model for large earthquakes, Seismicity and aseismic slip along the Eltanin fracture zone, Repeat times of large earthquakes: implications for earthquake mechanics and long-term prediction, Moderate and large earthquake activity along oceanic transform faults, Origin of the Louisville ridge and its relationship to the Eltanin fracture zone system, A new class of faults and their bearing on continental drift, Oceanic transform earthquakes with unusual mechanism or locations: relation to fault geometry and state of stress in the adjacent lithosphere, The Authors Geophysical Journal International 2011 RAS, Fault identification and reliability evaluation using an SVM model based on 3D seismic data volume, Surface waves at a fluid/double-porosity medium interface, Adjoint-state traveltime tomography for azimuthally anisotropic media in spherical coordinates, Defining the Yangtze-Cathaysia suture zone in south china using ambient noise tomography, Observations and simulations of the meteotsunami generated by the Tonga eruption on 15 January 2022 in the Mediterranean Sea, Volume 234, Issue 1, July 2023 (In Progress), Volume 233, Issue 3, June 2023 (In Progress), Volume 233, Issue 2, May 2023 (In Progress), Volume 233, Issue 1, April 2023 (In Progress), Geomagnetism, Rock Magnetism and Palaeomagnetism, Marine Geosciences and Applied Geophysics, Appendix B: Trade-off between scalarmoment estimates and depths of CMTS, https://doi.org/10.1111/j.1365-246X.2011.05284.x, Earthquake interaction, forecasting, and prediction, Oceanic transform and fracture zone processes, Receive exclusive offers and updates from Oxford Academic, Copyright 2023 The Royal Astronomical Society. L.R. VanDeMark
These species await a formal description and it is not known whether or not they represent communities distinct from those on the northern MAR. Small amounts of normal faulting occurring off transform is in accord with the idea that the Euler pole has moved relatively recently in time to place each of the three transform zones under a small component of extension. He found that interevent times for those pairs was tightly clustered around 5 yr with a COV ~ 0.2. 3) along the eastern part of the Heezen transform between +100 and +200 km (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. The maximum size of earthquakes along fast spreading ridges themselves is not greater than magnitude 3 (McGuire 2008; M. Tolstoy, personal communication, 2010). Sunrise, sunset, day length and solar time for Stockholm County. Haiti is situated on a transform boundary also known as a strike (2010) that describes the relative motion of the Pacific and Antarctic plates. Dziewonski
Ryan and M. Tolstoy for helpful discussions. and the Eurasian plate. It moves (1997) for the intermediate-period, fundamental-mode surface waves. In that simple model, earthquakes should extend to greater depths and presumably be larger near the centres of transforms, which is clearly not the case for the Heezen and Tharp faults. Ekstram
They also calculated Mw for three earthquakes in 1969, 1971 and 1973; they and Molnar et al.
4). .
[3], The Romanche Fracture Zone offsets the Mid-Atlantic ridge by 900km (560mi), making it the largest equatorial fracture zone in the Atlantic. We take this along with the distributions of events in time and longitude after 1976 (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.
Map view of CMT locations of earthquakes along Tharp transform from 1976 to 2010. 7, many of the smaller events are either aftershocks or foreshocks and are considered to be noise for the purposes of assessing the repeat times of the largest earthquakes.
5 contains only two earthquakes of Mw 5.45 and 5.50. 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. None of our normal-faulting solutions are found adjacent to that part of the Tharp transform. Shimazaki
The ridge segments and transform faults of the East Pacific Rise and Pacific-Antarctic ridge are the sites of the fastest rates of the seafloor spreading and relative plate motion in the world. They may be regarded as quasi-periodic. What are mid-ocean ridges? J.K.
(1993) for two other normal faulting earthquakes off the Eltanin transforms. A 30- to 42-km segment of the Heezen transform fault between 124.05 and 124.75 W was the site of eight shocks of Mw 5.93-6.07 from 1976 to 2010 (Figs 3 and 4) and possibly an earlier event in 1975. Hence, remote techniques such as seismicity and satellite altimetry provide important constraints on the tectonics, especially for the Tharp and Hollister transforms. 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. F.
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. 1975; Lonsdale 1994), which were named for M. Tharp, B. Heezen and C. Hollister . Surface waves have an advantage for precise locations over body waves since their velocity is much less. We assume that earthquakes along a given segment of a transform occur on single faults although the distribution of CMT solutions scatters about 15 km perpendicular to the transforms. Bergman
Although magmatism was more or less continuous on the ridge during 28-60 Ma, it probably occurred on crust . 4 occurred. The linearity of the CMT locations along the shorter Hollister transform (Fig. Excluding it does not change the average repeat time for events of Mw > 5.9; it increases the SD and COV slightly. 4. The two dotted lines in Fig. Map view of CMT locations of earthquakes along Heezen transform and easternmost end of Tharp transform from 1976 to 2010. 4. Most prominent is an asymmetric transverse ridge, at which abyssal hills adjacent to the fault zone have been . Since the length along strike, L, was not determined for individual earthquakes, for the calculations later we took a length of 105 km for the entire eastern end of the Heezen transform, which includes several segments that have ruptured in large shocks (Fig. (1975) obtained strike-slip mechanisms for them and another event in 1967. transform plate boundaries learning geology. We conclude that strike-slip and normal faulting along the three Eltanin transforms are partitioned so that strike-slip faulting takes place along the transforms themselves and normal faulting occurs nearby but just off the transforms. The existence of three or four plates in the region during those times permitted offset to grow across the Eltanin system (Watts et al. D.K. The continuity in smooth trend of the ridge and the Eltanin Fracture Zone suggests some relationship between them. New Mw corresponds to seismic moment magnitude recomputed for this study. Meteoritic Microfossils in Eltanin Impact Deposits. Molnar
Since the 40-km section of the Tharp (Fig. For the period 19902009, we rejected only one event, which occurred on 2001 August 6. 2. Wolfe et al. 3) to indicate stationarity of well-coupled and poorly coupled behaviour along transform segments since at least 1969.