Susan Schwartz

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2019 Barcheck, C.G., S.Y. Schwartz, S. Tulaczyk; Icequake streaks linked to potential mega-scale glacial lineations beneath an Antarctic ice stream. Geology ; 48 (2): 99–102. doi:

2019 Zal, H., K. Jacobs, M.K. Savage, J. Yarce, S. Mroczek, K. Graham, E.K. Todd, J. Nakai, Y. Iwasaki, A. Sheehan, K. Mochizuki, L. Wallace, S. Schwartz, S. Webb, and S. Henrys, Temporal and spatial variations in seismic anisotropy and vp/vs ratios in a region of slow slip, Earth and Planet. Sci. Lett., 532,

2019 Protti, M., Bangs, N., Baumgartner, P., Fisher, D., Kaneda, Y., LaFemina, P., Newman, A., Noren, A., Schwartz, S. Suyehiro, K., and Wiersberg, T. (2019), Osa Peninsula, Costa Rica: A unique opportunity to drill and instrument the seismogenic zone of large megathrustearthquakes, Temblor,

2019 Yarce, J., A.F. Sheehan, J.S. Nakai, S.Y. Schwartz, K. Mochizuki, M.K. Savage, L.M. Wallace, S.A. Henrys, S.C. Webb, Y. Ito, R.E. Abercrombie, B. Fry, H. Shaddox, and E.K. Todd, Seismicity at the Northern Hikurangi Margin, New Zealand, and Investigation of the Potential Spatial and Temporal Relationships With a Shallow Slow Slip Event, Journal of Geophysical Research: Solid Earth, 124.

2019 Warren-Smith, B. Fry, L. Wallace, 
E. Chon, S. Henrys, A. Sheehan, K. Mochizuki, S. Schwartz, S. Webb, S. Lebedev, Episodic stress and fluid pressure cycling in subducting oceanic crust during slow slip, Nature Geosicence, 12, 475-481.

2019 Shaddox, H. R., and Schwartz, S. Y., Subducted seamount diverts shallow slow slip to the forearc of the Northern Hikurangi Subduction Zone, New Zealand, Geology, doi:

2019 Abers, G. A., et al. (2019), Examining Alaska’s earthquakes on land and sea, Eos, 100,

2018 Voss, N., Dixon, T.H., Liu, Z., Malservisi, R., Protti, M., Schwartz, S.Y., Do slip events trigger large and great megathrust earthquakes?, Science Adv., 4, eeat8472.

2018 Todd, E.K., Schwartz, S.Y., Mochizuki, K., Wallace, L.M., Sheehan, A.F., Webb, S.C., et al. (2018). Earthquakes and tremor linked to seamount subduction during shallow slow slip at the Hikurangi Margin, New Zealand. Journal of Geophysical Research: Solid Earth, 123, 6769-6783, doi:10.1029/2018JB016136.

2018 Barcheck, C.G, Tulaczyk, S., Schwartz, S.Y., Walter, J.I., Winberry, J.P., Implications of basal microearthquakes and tremor for ice stream mechanics: Stick-slip basal sliding and till erosion, Earth and Planet. Sci Lett., 486, 54-60.

2017 Chaves, EJ, L. Duboeuf, S.Y. Schwartz, T. Lay, J. Kintner, Aftershocks of the 2012 (MW 7.6) Nicoya, Costa Rica Earthquake and Mechanics of the Plate Interface, Bull. Seismol. Soc. Am., Vol. 107, No. 3, pp. 1227-1239, doi: 10.1785/0120160283.

2017 Jiang, Y., Z. Liu, E.E. Davis, S.Y. Schwartz, T.H. Dixon, N. Voss, R. Malservisi, and M. Protti, Strain release at the trench during shallow slow slip: The example of Nicoya Peninsula, Costa Rica, Geophys. Res. Lett., DOI: 10.1002/2017GL072803.

2017 Yao, D., J. I. Walter, X. Meng, T. E. Hobbs, Z. Peng, A. V. Newman, S. Y. Schwartz, and M. Protti, Detailed spatiotemporal evolution of microseismicity and repeating earthquakes following the 2012 Mw 7.6 Nicoya earthquake, J. Geophys. Res. Solid Earth, 122, 524–542, DOI: 10.1002/2016JB013632.

2016 Todd, EK and SY Schwartz, Tectonic tremor along the northern Hikurangi Margin, New Zealand between 2010 and 2015, J. Geophys. Res., in revision.

2016 Chaves, EJ, L. Duboeuf, SY Schwartz, T. Lay, J. Kintner, Aftershocks of the 2012 (MW 7.6) Nicoya, Costa Rica Earthquake and Mechanics of the Plate Interface, Bull. Seismol. Soc. Am., in review.

2016 Gomberg, J., DC Agnew, and SY Schwartz, Alternative Source Models of Very Low Frequency Events, J. Geophys. Res., in press.

2016 Wallace, LM., SC. Webb, Y. Ito, K. Mochizuki, R. Hino, S. Henrys, SY Schwartz, AF Sheehan, Slow slip near the trench at the Hikurangi subduction zone, New Zealand Science, Vol. 352, Issue 6286, pp. 701-704, DOI: 10.1126/science.aaf2349.

2016 Chaves EJ and SY Schwartz, Monitoring transient changes within overpressured regions of subduction zones using ambient seismic noise, Science Advances,Vol. 2, no. 1, DOI: 10.1126/sciadv.1501289.

2016 Harris, R., L. Wallace, S. Webb, Y. Ito, K. Mochizuki, H. Ichihara, S. Henrys, A. Trehu, S. Schwartz, A. Sheehan, D. Saffer, and R. Lauer, Investigations of Shallow Slow Slip Offshore of New Zealand, EOS, VOL. 97, No. 10, pp. 20-23.

2015 Schwartz, SY, Episodic Aseismic Slip at Plate Boundaries, in The Treatise on Geophysics 2nd edition, Gerald Schubert (editor-in-chief), Oxford: Elsevier; 2015. pp. 445-465.

2015 Malservisi, R, Schwartz, SY, Voss, N, Protti, M, Gonzalez, V, Dixon, TH, Jiang, Y, Newman, AV, Richardson, J, Walter, JI and Voyenko, D, Multiscale postseismic behavior on a megathrust: The 2012 Nicoya earthquake, Costa Rica, Geochem. Geophys. Geosyst.,VOL. 16, ISSUE 6, DOI:10.1002/2015GC005794.

2015 Walter, JI, X Meng, Z Peng, SY Schwartz, AV Newman, M Protti, Far-field triggering of foreshocks near the nucleation zone of the 5 September 2012 (M-W 7.6) Nicoya Peninsula, Costa Rica earthquake, Earth Planet Sci Lett, Vol. 431, pp.75-86, DOI: 10.1016/j.epsl.2015.09.017.

2015 Xue, L., S. Schwartz, Z. Liu, and L. Feng, Interseismic megathrust coupling beneath the Nicoya Peninsula, Costa Rica, from the joint inversion of InSAR and GPS data, J. Geophys. Res. Solid Earth, 120, doi:10.1002/2014JB011844.

2015 Gao, H. and S. Schwartz, Preface to the Focus Section on Cascadia Initiative Preliminary Results, Seismol. Res. Lett., VOL. 85, ISSUE 5, pp. 1235-1237, DOI:10.1785/0220150160.

2014 Article: Tulaczyk, S., JA. Mikucki, MR. Siegfried, JC. Priscu, CG. Barcheck, LH. Beem, A. Behar, J. Burnett, BC. Christner, AT. Fisher, HA. Fricker, KD. Mankoff, RD. Powell, F. Rack, D. Sampson, RP. Scherer, SY. Schwartz and The WISSARD Science Team, WISSARD at Subglacial Lake Whillans, West Antarctica: scientific operations and initial observations, Annals of Glaciology 55(65), doi: 10.3189/2014AoG65A009.

2014 Toomey, D., RM. Allen, AH. Barclay, SW. Bell, PD. Bromirski, RL. Carlson, X. Chen, JA. Collins, RP. Dziak, B. Evers, DW. Forsyth, P. Gerstoft, EEE. Hooft, D. Livelybrooks, JA. Lodewyk, DS. Luther, JJ. McGuire, SY. Schwartz, M. Tolstoy, AM. Trehu, M. Wierathmueller, WSD. Wilcock, The Cascadia Initiative: A Sea Change in Seismological Studies of Subduction Zones, Oceanography, 27, 2, 116-128.

2014 Protti, M., v. Gonzalez, A.V. Newman, T.H. Dixon, S.Y. Schwartz, J.S. Marshall, L.J. Feng, J.I. Walter, R Malservisi, S.E. Owen, Nicoya earthquake rupture anticipated by geodetic measurement of the locked plate interface, Nature Geoscience, doi: 10.1038/NGEO2038.

2013 Yue, H., T. Lay, S.Y. Schwartz, L. Rivera, M. Protti, T.H. Dixon, S. Owen, A.V. Newman, The 5 September 2012 Nicoya, Costa Rica M-w 7.6 earthquake rupture process from joint inversion of high-rate GPS, strong-motion, and teleseismic P wave data and its relationship to adjacent plate boundary interface properties, Journal of Geophysical Research - Solid Earth, doi: 10.1002/jgrb.50379.

2013 Audet, P. and S.Y. Schwartz, Hydrologic control of forearc strength and seismicity in the Costa Rican subduction zone, Nature Geoscience, doi:10.1038/ngeo1927.

2013 Walter, J.I., S.Y. Schwartz, M. Protti, V. Gonzalez, The synchronous occurence of shallow tremor and very low frequency earthquakes offshore of the Nicoya Peninsula, Costa Rica, Geophyisacl Research Letters, doi: 10.1002/grl.50213.

2011 Kim, M.J., S.Y. Schwartz, S. Bannister, Non-volcanic tremor associated with the March 2010 Gisborne slow slip event at the Hikurangi subduction margin, New Zealand , Geophys. Res. Lett., doi: 10.1029/2011GL048400.

2011 Walter, J.I., E.E. Brodsky, S. Tulaczyk, S.Y. Schwartz, and R. Pettersson, Transient slip events from near-field seismic and geodetic data on a glacier-fault, Whillans Ice Plain, West Antarctica, J. Geophys. Res., doi:10.1029/2010JF001754.

2011 Walter, J.I., S.Y. Schwartz, M. Protti, V. Gonzalez, Persistent tremor within the northern Costa Rica seismogenic zone, Geophys. Res. Lett., doi: 10.1029/2010GL045586.

2010 Outerbridge, K.C., T. H. Dixon, S. Y. Schwartz, J. I. Walter, M. Protti, V. Gonzalez, J. Biggs, M.M. Thorwart, and W. Rabbel , A tremor and slip event on the Cocos-Caribbean Subduction zone as measured by a GPS and seismic network on the Nicoya Peninsula, Costa Rica, J. Geophys. Res., doi:10.1029/2009JB006845.

2010 Linkimer, L., S.L. Beck, S.Y. Schwartz, G. Zandt, and V. Levin, Nature of crustal terranes and the Moho in northern Costa Rica from receicer function analysis, Geochem, Geophys., and Geosystems, 11, doi:10.1029/2009GC002795.

2009 Brown, J.R., G. C. Beroza, S. Ide, K. Ohta, D. R. Shelly, S.Y. Schwartz, W. Rabbel, M. Thorwart, H. Kao, Deep Low Frequency Earthquakes in Tremor Localize to the Plate Interface in Multiple Subduction Zones, Geophys. Res. Lett., 36, L19306, doi:10.1029/2009GL040027.

2008 Hansen, S.E., J.B. Gaherty, S.Y. Schwartz, A.J. Rodgers, and A.M.S. Al-Amri, Seismic velocity structure and depth-dependence of anisotropy in the Red Sea and Arabian shield from surface wave analysis, J. Geophys. Res., 113, B10307, doi:10.1029/2007JB005335.

2007 Hansen, S.E., A.J. Rodgers, S.Y. Schwartz and A.M.S. Al-Amri, Imaging ruptured lithosphere beneath the Red Sea and Arabian Peninsula, Earth and Planet Sci. Lett., 259, 256-265.

2007 Schwartz, S.Y., Episodic Aseismic Slip at Plate Boundaries, in The Treatise on Geophysics, ed. G. Schubert, vol. 4, Earthquake Seismology, ed. H. Kanamori, Elsevier Press, Netherlands, ISBN: 0-444-51928-9.

2007 Schwartz, S.Y. and J.M. Rokosky, Slow Slip Events and Seismic Tremor at Circum-Pacific Subduction Zones, Rev. of Geophys, 45, RG3004, doi:10.1029/2006RG000208.

2007 Schwartz, S.Y. and H.R. DeShon, Distinct Up-dip Limits to Geodetic Locking and Microseismicity at the Northern Costa Rica Seismogenic Zone: Evidence for Two Mechanical Transitions, in The Seismogenic Zone of Subduction Thrust Faults, eds. T. Dixon and J.C. Moore, Columbia Univerisity Press, New York, 576-599.

2006 DeShon, H.R., S.Y. Schwartz, A.V. Newman, V. Gonzalez, J.M. Protti, L.M. Dorman, T. Dixon, E. Norabuena, and E. Flueh, Seismogenic zone structure beneath the Nicoya Peninsula, Costa Rica, from 3D local earthquake P- and S- wave tomography, Geophys. J. Int., 164, 109-124.

2006 Hansen, S., S. Schwartz, A. Al-Amri and A. Rodgers, Combined plate motion and density-driven flow in the asthenosphere beneath Saudi Arabia: Evidence from shear-wave splitting and seismic anisotropy, Geology, 34, 869-872.

2006 Hansen, S.E., S.Y. Schwartz, H.R. DeShon and V. Gonzalez, Earthquake relocation and focal mechanism determination using waveform cross-correleation, Nicoya Peninsula, Costa Rica, Bull. Seismol. Soc. Am., 96, 1003-1011.

2005 Brown, K.M., M. Tryon, H.R. DeShon, L.M. Dorman, and S.Y. Schwartz, Transient fluid pulsing and seismic tremor: Evidence of episodic creep at the updip edge of the seismogenic zone, Costa Rica, Earth and Planet. Sci. Lett., 238, 189-203.

2004 DeShon, H.R. and S.Y. Schwartz, Evidence for serpentinization of the forearc mantle wedge along the Nicoya Peninsula, Costa Rica, Geophys. Res. Lett., 31,doi:10.1029/2004GL021179.

2004 Norabuena, E., T.H. Dixon, S. Schwartz, H. DeShon, A. Newman, M. Protti,V. Gonzalez, L. Dorman, E.R. Flueh, P. Lundgren, F. Pollitz, and D. Sampson, Geodetic and Seismic Constraints on Some Seismogenic Zone Processes in Costa Rica, J. Geophys. Res., 109, doi:10.1029/2003JB002931.

2004 Lay, T. and S.Y. Schwartz, Comment on “Coupling Semantics and Science in Earthquake Research”, EOS, Trans. Am. Geophys. Union, 85 (36), 339-340.

2003 DeShon, H.R., S.Y. Schwartz, S.L. Bilek, L.M. Dorman, V. Gonzalez, J.M. Protti, E.R. Flueh and T.H. Dixon, Seismogenic zone structure of the southern Middle America Trench, Costa Rica, J. Geophys. Res., 108, doi:10.1029/2002JB002294.

2003 Vallee, M, M. Bouchon and S.Y. Schwartz, The 13 January 2001 El Salvador earthquake: A multidata analysis, J. Geophys. Res., 108(B4):2203.

2003 Bilek, S.L., S.Y. Schwartz and H. R. DeShon, Control of seafloor roughness on earthquake rupture behavior, Geology, 31(5):455-458.

2002 Newman, A.V., S.Y. Schwartz, V. Gonzalez, H.R. DeShon, J.M. Protti, and L.M. Dorman, Along-strike variability in the seismogenic zone below Nicoya Peninsula, Costa Rica, Geophys. Res. Lett., 29, doi:10.1029/2002GL015409.

2001 Hartog, R. and S.Y. Schwartz, Depth-dependent mantle anisotropy below the San Andreas fault system: Apparent splitting parameters and waveforms, J. Geophys Res., 106, 4155-4167.

2000 Hartog, R. and S.Y. Schwartz, Subduction-induced strain in the upper mantle east of the Mendocino triple junction, California, J. Geophys. Res., 105, 7909-7930.

2000 Hagerty, M.T., S.Y. Schwartz, M.A. Garces and M. Protti, Analysis of seismic and acousitc observations at Arenal Volcano, Costa Rica 1995-1997, J. Volcanology and Geothermal Res., 101, 27-65.

1999 Schwartz, S.Y., Noncharacteristic behavior and complex recurrence of large subduction zone earthquakes, J. Geophys. Res., 104, 23,111-23,125.

1998 Garces, M.A., M.T. Hagerty, and S.Y. Schwartz, Magma acoustics and time-varying melt properties at Arenal Volcano, Costa Rica, Geophys. Res. Lett., 25, 2293-2296.

1998 Rodgers, A. J., and S. Y. Schwartz, Lithospheric structure of the Qiangtang Terrane, northern Tibetan Plateau from complete regional waveform modelling: Evidence for partial melt, J. Geophys. Res., 103, 7137-7152.

1997 Hagerty, M., S.Y. Schwartz, M. Protti, M. Garces, and T. Dixon, Observations at Costa Rican Volcano offer clues to causes of eruptions, EOS, Trans. Am. Geophys. Union, 78, 565, 570-571.

1997 Schwartz, S.Y. and G. Nelson, Loma Prieta aftershock relocation with S-P travel times from a portable array, in The Loma Prieta, California, Earthquake of October 17, 1989 - Postseismic effects, aftershocks and observations , ed. P. Reasenberg, U.S. Geological Survey Prof. Paper 1550-D, 91-103.

1997 Goes, S.,R. Govers,S.Y. Schwartz, andK.P. Furlong, Three-dimensional thermal modeling for the Mendocino Triple Junction area, Earth and Planet. Sci. Lett., 148, 45-57.

1997 Schwartz, S.Y., and A. Hubert, The state of stress near the Mendocino Triple Junction from inversion of earthquake focal mechanisms, Geophys. Res. Lett., 24, 1263-1266.

1997 Rodgers, A. J. and S.Y. Schwartz, Low crustal velocities and mantle lithospheric variations in southern Tibet from regional Pnl waveforms, Geophys. Res. Lett., 24, 9-12.

1996 Hagerty, M. T., and S.Y. Schwartz, The 1992 Cape Mendocino Earthquake: Broadband determination of source parameters, J. Geophys. Res., 101, 16,043-16,058.

1996 Xu, Z., S.Y. Schwartz, and T. Lay, Seismic wavefield observations at a dense, small aperture array located on a landslide in the Santa Cruz Mountains, California, Bull.Seismol. Soc. Am., 86,655-669.

1996 Zhang, T., T. Lay, S.Y. Schwartz and W.R. Walter, Variation of regional seismic discriminants with surface topographic roughness in the western United States, Bull. Seismol. Soc. Am., 86, 714-725.

1996 Hartog, R., and S.Y. Schwartz, Directivity analysis of the December 1994 Sanriku-Oki earthquakes (Mw=7.7), Geophys. Res. Lett., 23, 2037-2040. 1996 Protti, M., S.Y. Schwartz, and G. Zandt, Simultaneous inversion for earthquake location and velocity structure beneath Costa Rica, Bull. Seismol. Soc. Am., 86, 19-31.

1995 Schwartz, S.Y., Source parameters of aftershocks of the 1991 Costa Rica and 1992 Cape Mendocino, California earthquakes from inversion of local amplitude ratios and broadband waveforms, Bull. Seismol. Soc. Am., 85, 1560-1575.

1994 Protti, M., and S.Y. Schwartz, Mechanics of back-arc deformation in Costa Rica: Evidence from an aftershock study of the April 22, 1991 Valle de la Estrella, Costa Rica earthquake (Mw=7.7), Tectonics.,13, 1093-1107.

1994 Beckers, J., S.Y. Schwartz, and T. Lay, The velocity structure of the crust and upper mantle under China from broadband P and PP waveform analysis, Geophys. J. Int., 119, 574-594.

1994 Zhang, T., S.Y. Schwartz, and T. Lay, Multivariate analysis of waveguide effects on short-period regional wave propagaion in Eurasia and its application in seismic discrimination, J. Geophys. Res., 99, 21,929-21,945.

1993 Schwartz, S.Y., and T. Lay, Complete synthetic PP waveforms and their use in determining crust and upper mantle structure, Geophys. J. Int., 112, 210-224.

1993 Goes, S., A. Velasco, S.Y. Schwartz, and T. Lay, The April 22, 1991, Valle de la Estrella, Costa Rica (Mw=7.7) earthquake and its tectonic implications: A broadband seismic study, J. Geophys. Res., 98, 8127-8142.

1993 Xu, Z., and S.Y. Schwartz, Large earthquake doublets and fault plane heterogeneity in the Northern Solomon Islands subduction zone, Pageoph, 140, 365-390.

1993 Houston, H., H. Anderson, S.L. Beck, J. Zhang, and S.Y. Schwartz, The 1986 Kermadec earthquake and its relation to plate-segmentation., Pageoph, 140, 331-364.

1992 Zhang Z., and S.Y. Schwartz, Depth distribution of moment release in underthrusting earthquakes at subduction zones, J. Geophys. Res., 97, 537-544. 1992 Schwartz, S.Y., Earthquake mobilization plan tested, EOS, Trans. Am. Geophys. Union, 73, 277-278.

1991 Bonamassa, O., J.E. Vidale, H. Houston and S.Y. Schwartz, Directional site resonances and the influence of near-surface geology on ground motion, Geophys. Res. Lett., 18, 901-904.

1991 Schwartz, S.Y., T. Lay, and S.L. Beck, Shear wave travel time, amplitude, and waveform analysis for earthquakes in the Kurile Slab: Constraints on deep slab structure and mantle heterogeneity, J. Geophys. Res., 96, 14,445-14,460.

1991 Schwartz, S.Y., T. Lay, and S. P. Grand, Seismic imaging of subducted slabs: Trade-offs with deep path and near-receiver effects, Geophys. Res. Lett., 18, 1265-1268.

1991 Schwartz, S.Y., and G. Nelson, Loma Prieta aftershock relocation with S-P travel times: Effects of 3-D structure and true error estimates, Bull. Seismol. Soc. Am., 81, 1705-1725.

1990 Schwartz, S.Y., D.L. Orange, and R.S. Anderson, Complex fault interactions in a restraining bend on the San Andreas Fault, Southern Santa Cruz Mountains, California, Geophys. Res. Lett., 17, 1207-1210. Also published in: The Loma Prieta, California, Earthquake of October 17, 1989- Tectonic Processes and Models, U.S. Geological Survey Prof. Paper 1550-F, F49-54, 1994.

1989 Schwartz, S.Y., J.W. Dewey, and T. Lay, Influence of fault plane heterogeneity on the seismic behavior in the southern Kurile Islands Arc, J. Geophys. Res., 94, 5637-5649.

1989 Schwartz, S.Y., T. Lay, and L.J. Ruff,. Source process of the great 1971 Solomon Islands Doublet, Phys. Earth and Planet. Int., 56, 294-310.

1988 Schwartz, S.Y. and D.H. Christensen, The 12 July 1986 St. Marys, Ohio earthquake and recent seismicity in the Anna, Ohio seismogenic zone, Seism. Res. Lett., 59, 57-62.

1988 Schwartz, S.Y., and T. Lay, Analysis of upper mantle P wave velocity structure beneath N. America and Eastern Europe using P and PP phases, in Fourth EGT Workshop: The upper mantle, eds. G. Nolet and B. Dost, European Science Foundation, 119-127.

1987 Schwartz, S.Y., and L.J. Ruff, Asperity distribution in the southern Kurile Islands arc, Phys. Earth Planet Int., 49, 54-77.

1987 Schwartz, S.Y., and T. Lay, Effects of off-great-circle propagation on the phase of long-period surface waves, Geophys. J.R. astron. Soc., 91, 143-154.

1985 Schwartz, S.Y., and L.J. Ruff, The 1968 Tokachi-Oki and the 1969 Kurile Islands earthquakes: Variability in the rupture process, J. Geophys. Res., 90, 8613-8626.

1985 Schwartz, S.Y., and T. Lay, Comparison of long-period surface wave amplitude and phase anomalies for two models of lateral heterogeneity, Geophys. Res. Lett., 12, 231-234.

1984 Schwartz, S.Y., and Rob Van der Voo, Reply to 'The orocline hypothesis versus thin skin rotation in the central and southern Appalachians by I.B. Alterman, Geophys. Res. Lett., 11, 90.

1984 Schwartz, S.Y., and Rob Van der Voo, Paleomagnetic study of thrust sheet rotation during foreland impingement in the Wyoming-Idaho overthrust belt, J. Geophys. Res., 89, 10077-10086.

1983 Schwartz, S.Y., and Rob Van der Voo, Paleomagnetic evaluation of the orocline hypothesis in the central and southern Appalachians, Geophys. Res. Lett., 10, 505-508.