An updated digital model of plate boundaries

Abstract

[1] A global set of present plate boundaries on the Earth is presented in digital form. Most come from sources in the literature. A few boundaries are newly interpreted from topography, volcanism, and/or seismicity, taking into account relative plate velocities from magnetic anomalies, moment tensor solutions, and/or geodesy. In addition to the 14 large plates whose motion was described by the NUVEL-1A poles (Africa, Antarctica, Arabia, Australia, Caribbean, Cocos, Eurasia, India, Juan de Fuca, Nazca, North America, Pacific, Philippine Sea, South America), model PB2002 includes 38 small plates (Okhotsk, Amur, Yangtze, Okinawa, Sunda, Burma, Molucca Sea, Banda Sea, Timor, Birds Head, Maoke, Caroline, Mariana, North Bismarck, Manus, South Bismarck, Solomon Sea, Woodlark, New Hebrides, Conway Reef, Balmoral Reef, Futuna, Niuafo'ou, Tonga, Kermadec, Rivera, Galapagos, Easter, Juan Fernandez, Panama, North Andes, Altiplano, Shetland, Scotia, Sandwich, Aegean Sea, Anatolia, Somalia), for a total of 52 plates. No attempt is made to divide the Alps-Persia-Tibet mountain belt, the Philippine Islands, the Peruvian Andes, the Sierras Pampeanas, or the California-Nevada zone of dextral transtension into plates; instead, they are designated as ''orogens'' in which this plate model is not expected to be accurate. The cumulative-number/area distribution for this model follows a power law for plates with areas between 0.002 and 1 steradian. Departure from this scaling at the small-plate end suggests that future work is very likely to define more very small plates within the orogens. The model is presented in four digital files: a set of plate boundary segments; a set of plate outlines; a set of outlines of the orogens; and a table of characteristics of each digitization step along plate boundaries, including estimated relative velocity vector and classification into one of 7 types (continental convergence zone, continental transform fault, continental rift, oceanic spreading ridge, oceanic transform fault, oceanic convergent boundary, subduction zone). Total length, mean velocity, and total rate of area production/destruction are computed for each class; the global rate of area production and destruction is 0.108 m 2 /s, which is higher than in previous models because of the incorporation of back-arc spreading.

Geodetic constraints on active tectonics of the Western Mediterranean: Implications for the kinematics and dynamics of the Nubia-Eurasia plate boundary zone

“…These estimates are within the range of geological rates that constrain shortening to about 1 to 2 mm/yr across the entire Atlas 130 mountain system (Meghraoui et al, 1998;Gomez et al, 2000). (Bird, 2003) or north of Gibraltar in the Betic Cordillera (Gutscher, 2004). The best fit is for models where the boundary passes through the 170 Gibraltar Strait (Klitgord and Schouten, 1986).…”

“…The slab must be narrow since the lateral extent of the southward motion is only 150-200 km, making it a challenge to image with seismological methods. (Klitgord and Schouten, 1986), green (Bird, 2003), and blue (Gutscher, 2004). Crustal earthquake focal mechanisms are from Harvard catalog (magnitudes 5-6.5, 1976 -2008).…”

Great earthquakes and slab pull: interaction between seismic coupling and plate–slab coupling

“…5b), despite having the fastest overriding plate motion toward the subduction zone. In this case, however, the overriding plate may be broken into several smaller plates [46,47] that shield the slab from the compression associated with trenchward motion of the Paci¢c plate. This lack of compression is evident in the strong back-arc spreading observed for this subduction zone (Fig.…”

A precise bathymetric map of the world’s deepest seafloor, Challenger Deep in the Mariana Trench

“…The index map shows the location of this map relative to other northwest Pacific features. The red lines represent the present plate boundaries from Bird (2003). PAC, PHI, and CAR denote Pacific, Philippine Sea, and Caroline plates, respectively …”