We use cookies to ensure that we give you the best experience on our website. You can change your cookie settings at any time. Otherwise, we'll assume you're OK to continue.

Durham University

Department of Earth Sciences


Publication details for Prof Roger Clive Searle

Neves, M.C., Bott, M.H.P. & Searle, R.C. (2004). Patterns of stress at midocean ridges and their offsets due to seafloor subsidence. Tectonophysics 386(3-4): 223-242.

Author(s) from Durham


The effect of the seafloor subsidence on the horizontal stress field of young oceanic lithosphere is investigated by combining the finite element method with a formulation that allows us to compute the two-dimensional horizontal stresses arising from isostatically compensated vertical loads. We find that the topographic load created by the elevation of mid-ocean ridges relative to old ocean floor is a significant source of ridge-parallel tensile stresses. These may predominate over the ridge-perpendicular stresses and explain observations at mid-ocean ridge offsets such as (1) oblique normal faulting at ridge-transform intersections trending up to 60º relative to the ridge axis, and (2) non-transform offsets consisting of extensional basins oriented at 45º relative to the ridge trend. At mid-ocean ridge overlaps, rotation of the ridge-parallel tensile stresses favours rift propagation at more than 45º relative to the ridge trend. It is suggested that propagating rift tips that bend abruptly lead to partially unlocked offsets, and as a result large overlaps may eventually start to rotate and evolve into a microplate.


Anderson, E.M., 1951. The Dynamics of Faulting and Dyke
Formation with Applications to Britain. Oliver and Boyd,
Edinburgh, pp. 206.
Artyushkov, E.V., 1973. Stresses in the lithosphere caused by
crustal thickness inhomogeneities. J. Geophys. Res. 78 (32),
Behn, M., Lin, J., Zuber, M.T., 2002. Evidence for weak oceanic
transform faults. Geophys. Res. Lett. 29, 2207.
Bergman, E.A., Solomon, S.C., 1984. Source mechanisms of
earthquakes near mid-ocean ridges from body waveform
inversion: implications for the early evolution of oceanic
lithosphere. J. Geophys. Res. 89 (B13), 11415– 11441.
Bicknell, J.D., Sempere, J.-C., Macdonald, K.C., 1987. Tectonics
of a fast spreading center: a deep-tow and sea beam survey
on the East Pacific Rise at 19830VS. Mar. Geophys. Res. 9,
25– 45.
Bird, P., Piper, K., 1980. Plane-stress finite-element models of
tectonic flow in southern California. Phys. Earth Planet. Inter.
21, 158–175.
Bott, M.H.P., 1997. Modeling the formation of a half graben
using realistic upper crustal rheology. J. Geophys. Res. 102,
Bott, M.H.P., Kusznir, N.J., 1984. The origin of the tectonic stress in
the lithosphere. Tectonophysics 105, 1 – 13.
Bratt, S.R., Bergman, E.A., Solomon, S.C., 1985. Thermoelastic
stress: how important as a cause of earthquakes in young
oceanic lithosphere? J. Geophys. Res. 90 (B12), 10249– 10260.
Brune, J.N., Henyey, T.L., Roy, R.F., 1969. Heat flow, stress and
rate of slip along the San Andreas Fault. J. Geophys. Res. 74,
Carbotte, S.M., Macdonald, K.C., 1994. Comparison of seafloor
tectonic fabric at intermediate, fast, and super fast spreading
ridges: influence of spreading rate, plate motions, and ridge
segmentation on fault patterns. J. Geophys. Res. 99 (B7),
Cessaro, R.K., Hussong, D.M., 1986. Transform seismicity at the
intersection of the oceanographer fracture zone and the Mid-
Atlantic Ridge. J. Geophys. Res. 91 (B5), 4839–4853.
Chen, Y., Morgan, W.J., 1990. A nonlinear rheology model for
mid-ocean ridge axis topography. J. Geophys. Res. 95,
Cloetingh, S., Wortel, R., 1986. Stress in the Indo-Australian plate.
Tectonophysics 132, 49–67.
Collette, B.J., 1974. Thermal contraction joints in a spreading
seafloor as origin of fracture zones. Nature 251, 299– 300.
Crane, K., 1976. The intersection of the Siqueiros transform fault
and the East Pacific Rise. Mar. Geol. 21, 25– 46.
Dahlen, F.A., 1981. Isostasy and the ambient state of stress in the
oceanic lithosphere. J. Geophys. Res. 86 (B9), 7801– 7807.
England, P., McKenzie, D.P., 1982. A thin viscous sheet model
for continental deformation. Geophys. J. R. Astron. Soc. 70,
295– 321.
Escartin, J., Cowie, P.A., Searle, R.C., Allerton, S., Mitchell, N.C.,
MacLeod, C.J., Slootweg, A.P., 1999. Quantifying tectonic
strain and magmatic accretion at a slow spreading ridge
segment, Mid-Atlantic Ridge, 298N. J. Geophys. Res. 104
(B5), 10421– 10437.
Fleitout, L., Froidevaux, C., 1982. Tectonics and topography for a
lithosphere containing density heterogeneities. Tectonics 1 (1),
21– 56.
Fleitout, L., Froidevaux, C., 1983. Tectonic stresses in the
lithosphere. Tectonics 2 (3), 315– 324.
Flesch, L.M., Haines, A.J., Holt, W.E., 2001. Dynamics of the
India–Eurasia collision zone. J. Geophys. Res. 106 (B8),
16435– 16460.
Fornari, D.J., Gallo, D.G., Edwards, M.H., Madsen, J.A., Perfit,
M.R., Shor, A.N., 1989. Structure and topography of the
Siqueiros transform fault system: evidence for the development
of intra-transform spreading centers. Mar. Geophys. Res. 11,
263– 299.
Fox, P.J., Gallo, D.G., 1984. A tectonic model for ridge-transformridge
plate boundaries: implications for the structure of oceanic
lithosphere. Tectonophysics 104, 205–242.
Fox, P.J., Gallo, D.G., 1986. The geology of North Atlantic
transform plate boundaries and their aseismic extensions. In:
Vogt, P.R., Tucholke, B.E. (Eds.), The Geology of North
America, vol. M. The Western North Atlantic Region, Geol.
Soc. Am., pp. 157– 172.
Fujita, K., Sleep, N.H., 1978. Membrane stresses near mid-ocean
ridge-transform intersections. Tectonophysics 50, 207– 221.
Gallo, D.G., Fox, P.J., 1982. Changes in relative plate motion:
propagating ridges and the generation of oceanic microplates
along accreting plate boundaries. EOS, Trans. Am. Geophys.
Union 63, 446.
Gallo, D.G., Fox, P.J., Macdonald, K.C., 1986. A sea beam
investigation of the Clipperton transform fault: the morphotectonic
expression of a fast slipping transform boundary.
J. Geophys. Res. 91 (B3), 3455–3467.
Goodman, R.E., Taylor, R.L., Brekke, T.L., 1968. A model for the
mechanics of jointed rock. J. Soil Mech. Found. Div. Am. Soc.
Civ. Eng. 94, 637– 658.
Gordon, R.G., 2000. Diffuse oceanic plate boundaries: strain rates,
vertically averaged rheology, and comparison with narrow plate
boundaries and stable plate interiors in the history and dynamics
of global plate motions. Geophys. Monogr. Ser. 121, 143– 159.
Grindlay, N.R., Fox, P.J., 1993. Lithospheric stresses associated
with nontransform offsets of the Mid-Atlantic Ridge:
implications from a finite element analysis. Tectonics 12 (4),
982– 1003.
Grindlay, N.R., Fox, P.J., Macdonald, K.C., 1991. Second-order
ridge axis discontinuities in the South Atlantic: morphology,
structure and evolution. Mar. Geophys. Res. 13, 21– 49.
Gudmundsson, A., 1993. On the structure and formation of fracture
zones. Terra Nova 5, 215–224.
Gudmundsson, A., 1995. Stress field associated with oceanic
transform faults. Earth Planet. Sci. Lett. 136, 603– 614.
Haxby, W.F., Parmentier, E.M., 1988. Thermal contraction and the
state of stress in the oceanic lithosphere. J. Geophys. Res. 93
(B6), 6419– 6429.
Hey, R.N., Johnson, P.D., Martinez, F., Korenaga, J., Somers, M.L.,
Huggett, Q.J., LeBas, T.P., Rusby, R.I., Naar, D.F., 1995. Plate
boundary reorganisation at a large-offset, rapidly propagating
rift. Nature 378, 167– 170.
Houseman, G., England, P., 1993. Crustal thickening versus lateral
expulsion in the Indian–Asian continental collision. J. Geophys.
Res. 98, 12233–12249.
Huang, P.Y., Solomon, S.C., 1988. Centroid depths of mid-ocean
ridge earthquakes: dependence on spreading rate. J. Geophys.
Res. 93 (B11), 13445– 13477.
Jaeger, J.C., 1969. Elasticity, Fracture and Flow, with Engineering
and Geological Applications. Methuen & Co., London, p. 268.
Karson, J.A., Dick, H.J.B., 1983. Tectonics of ridge-transform
intersections at the Kane fracture-zone. Mar. Geophys. Res. 6,
Kastens, K.A., Ryan, W.B.F., Fox, P.J., 1986. Structural and
volcanic expression of a fast slipping ridge-transform-ridgeplate
boundary: sea MARC I and photographic surveys at the
Clipperton transform fault. J. Geophys. Res. 91, 3469–3488.
Kong, L.S.L., Solomon, S.C., Purdy, G.M., 1992. Microearthquake
characteristics of a mid-ocean ridge along-axis high. J. Geophys.
Res. 97, 1659–1685.
Kuo, B.Y., Forsyth, D.W., Parmentier, E.M., 1986. Flexure and
thickening of the lithosphere at the East Pacific Rise. Geophys.
Res. Lett. 13, 681– 684.
Kusznir, N.J., 1991. The distribution of stress with depth in the
lithosphere: thermo-rheological and geodynamic constraints.
Philos. Trans. R. Soc. Lond., A 337, 95–110.
Lachenbruch, A.H., 1973. A simple mechanical model for oceanic
spreading centers. J. Geophys. Res. 78 (17), 3395– 3417.
Lachenbruch, A.H., Sass, J.H., 1981. Corrections to dHeat flow and
energetics of the San Andreas fault zoneT and some additional
comments on the relation between fault friction and observed
heat flow. J. Geophys. Res. 86, 7171–7172.
Lachenbruch, A.H., Thompson, G.A., 1972. Oceanic ridges and
transform faults: their intersection angles and resistance to plate
motion. Earth Planet. Sci. Lett. 15, 116– 122.
Lin, J., Parmentier, E.M., 1990. A finite amplitude necking model
of rifting in brittle lithosphere. J. Geophys. Res. 95, 4909–4923.
Lonsdale, P., 1978. Near-bottom reconnaissance of a fast-slipping
transform fault zone at the Pacific–Nazca plate boundary.
J. Geol. 86, 451– 472.
Macdonald, K.C., Fox, P.J., 1983. Overlapping spreading centres:
new accretion geometry on the East Pacific Rise. Nature 302,
Macdonald, K.C., Kastens, K., Spiess, F.N., Miller, S.P., 1979. Deep
tow studies of the Tamayo transform fault. Mar. Geophys. Res.
4, 37–70.
Macdonald, K.C., Castillo, D.A., Miller, S.P., Fox, P.J., Kastens,
K.A., Bonatti, E., 1986. Deep-Tow studies of the Vema Fracture
Zone: 1. Tectonics of a major slow slipping transform fault and
its intersection with the Mid-Atlantic Ridge. J. Geophys. Res. 91
(B3), 3334–3354.
McKenzie, D., Jackson, J., 1983. The relationship between strain
rates, crustal thickening, palaeomagnetism, finite strain and fault
movements within a deforming zone. Earth Planet. Sci. Lett. 65,
Menard, H.W., Atwater, T.M., 1968. Changes in direction of
seafloor spreading. Nature 219, 463– 469.
Mithen, D.P., 1980. Numerical investigations into the mechanism of
graben formation. PhD Thesis, University of Durham.
Molnar, P., Tapponnier, P., 1975. Cenozoic tectonics of Asia: effects
of continental collision. Science 189, 419–425.
Mount, V.S., Suppe, J., 1992. Present-day stress orientations
adjacent to active strike-slip faults: California and Sumatra.
J. Geophys. Res. 97 (B8), 11995–12013.
Naar, D.F., Hey, R.N., 1991. Tectonic evolution of the Easter
microplate. J. Geophys. Res. 96, 7961–7993.
Neves, M.C., Searle, R.C., Bott, M.H.P., 2003. The dynamics of
Easter microplate. J. Geophys. Res. 108 (B4), 2213.
Owen, D.R.J., Hinton, E., 1980. Finite Elements in Plasticity:
Theory and Practice. Pineridge Press, Swansea, p. 594.
Parmentier, E.M., Haxby, W.F., 1986. Thermal-stresses in the
oceanic lithosphere—evidence from geoid anomalies at fracture
zones. J. Geophys. Res. 91 (B7), 7193– 7204.
Parsons, B., Richter, F.M., 1980. A relation between the driving
force and geoid anomaly associated with mid-ocean ridges.
Earth Planet. Sci. Lett. 51, 445– 450.
Parsons, B., Sclater, J.G., 1977. An analysis of the variation of
ocean floor bathymetry and heat flow with age. J. Geophys. Res.
82 (5), 803–827.
Phipps Morgan, J., Parmentier, E.M., 1984. Lithospheric stress near
a ridge-transform intersection. Geophys. Res. Lett. 11 (no. 2),
113– 116.
Phipps Morgan, J., Parmentier, E.M., Lin, J., 1987. Mechanisms for
the origin of mid-ocean ridge axial topography: implications for
the thermal and mechanical structure of accreting plate
boundaries. J. Geophys. Res. 92, 12823–12836.
Pockalny, R.A., 1997. Evidence of transpression along the
Clipperton transform: implications for processes of
plate boundary reorganization. Earth Planet. Sci. Lett. 146,
449– 464.
Pollard, D.D., Aydin, A., 1984. Propagation and linkage of oceanic
ridge segments. J. Geophys. Res. 89 (B12), 10017– 10028.
Provost, A.S., Houston, H., 2001. Orientation of the stress field
surrounding the creeping section of the San Andreas Fault:
evidence for a narrow mechanically weak fault zone. J. Geophys.
Res. 106 (B6), 11373– 11386.
Reinecker, J., Heidbach, O., Mueller, B., 2003. The 2003 release of
the World Stress Map., available
on line.
Sandwell, D.T., 1986. Thermal-stress and the spacing of transform
faults. J. Geophys. Res. 91 (B6), 6405– 6417.
Searle, R.C., 1983. Multiple, closely spaced transform faults in fastslipping
fracture zones. Geology 11, 607–610.
Searle, R.C., 1984. GLORIA survey of the East Pacific Rise near
3.58S: tectonic and volcanic characteristics of a fast-spreading
mid-ocean rise. Tectonophysics 101, 319–344.
Searle, R.C., 1986. GLORIA investigations of oceanic fracture
zones: comparative study of the transform fault zone. J. Geol.
Soc. (Lond.) 143, 743–756.
Searle, R.C., Laughton, A.S., 1977. Sonar studies of the Mid-
Atlantic Ridge and Kurchatov Fracture Zone. J. Geophys. Res.
82 (33), 15313– 15328.
Searle, R.C., Bird, R.T., Rusby, R.I., Naar, D.F., 1993. The
development of two oceanic microplates: Easter and Juan
Fernandez microplates, East Pacific Rise. J. Geol. Soc. (Lond.)
150, 965–976.
Shaw, P.R., 1992. Ridge segmentation, faulting and crustal thickness
in the Atlantic Ocean. Nature 358, 490–493.
Sleep, N.H., Rosendahl, B.R., 1979. Topography and tectonics of
mid-oceanic ridge axes. J. Geophys. Res. 84, 6831–6839.
Stein, S., Pelayo, A., 1991. Seismological constraints on stress in
the oceanic lithosphere. Philos. Trans. R. Soc. Lond., A 337,
53– 72.
Sykes, L.R., 1967. Mechanism of earthquakes and nature of faulting
on the mid-oceanic ridges. J. Geophys. Res. 72 (8), 2131– 2153.
Tamsett, D., Searle, R.C., 1988. Structure and development of the
mid-ocean ridge plate boundary in the Gulf of Aden: evidence
from GLORIA sidescan sonar. J. Geophys. Res. 93, 3157– 3178.
Tapponnier, P., Francheteau, J., 1978. Necking of the lithosphere and
the mechanics of slowly accreting plate boundaries. J. Geophys.
Res. 83, 3955– 3970.
Toomey, D.R., Solomon, R.C., Purdy, G.M., 1988. Microearthquakes
beneath the median valley of the Mid-Atlantic Ridge
near 238N: tomography and tectonics. J. Geophys. Res. 93,
Tucholke, B.E., Schouten, H., 1988. Kane Fracture Zone. Mar.
Geophys. Res. 10, 1– 39.
Turcotte, D.L., 1974. Are transform faults thermal contraction
cracks? J. Geophys. Res. 79 (17), 2573–2577.
Turcotte, D.L., Oxburgh, E.R., 1973. Mid-plate tectonics. Nature
244, 337– 339.
Turcotte, D.L., Schubert, G., 1982. Geodynamics: Applications of
Continuum Physics to Geological Problems. Wiley, New York,
p. 450.
Wang, X., Cochran, J.R., 1993. Gravity anomalies, isostasy, and
mantle flow at the East Pacific Rise crest. J. Geophys. Res. 98,
19505– 19531.
Watts, A.B., 2001. Isostasy and Flexure of the Lithosphere.
Cambridge Univ. Press, Cambridge. 458 pp.
Wiens, D.A., Stein, S., 1984. Intraplate seismicity and stresses
in young oceanic lithosphere. J. Geophys. Res. 89 (B13),
Wiens, D.A., Stein, S., 1985. Implications of oceanic intraplate
seismicity for plate stresses, driving forces and rheology.
Tectonophysics 116, 143– 162.
Zoback, M.D., 1991. State of stress and crustal deformation
along weak transform faults. Philos. Trans. R. Soc. Lond. 337,
141– 150.
Zoback, M.L., 1992. First- and second-order patterns of stress in the
lithosphere: the World Stress Map project. J. Geophys. Res. 97
(B8), 11703–11728.
Zoback, M.D., 2000. Strength of the San Andreas. Nature 405,
31– 32.