Finite-difference modelling for P-pulse propagation in elastic media with arbitrary polygonal surface
Article Sidebar
Main Article Content
Abstract
The applicability of the finite-difference methods has been limited in most cases to simple geometric shapes. The problem of introducing boundary conditions into the scheme has usually restricted the models to structures in which the boundaries are parallel to the coordinates. Recently, several investigators have studied the effect of prominent topographic features on seismic signals. Most deal with SH waves. The behaviour of a P-SV pulse in media with prominent irregular surfaces is yet almost unknown. The difficulty of the last problem relative to the SH case lies in the vectorial form of the equation of motion and the more complicated boundary conditions. In the present work a technique is proposed for simulating the P-SV wave propagation in a two-dimensional half-space with an arbitrary polygonlike topography. This technique has been applied to compute seismograms due to a P-pulse on surfaces of ridges and canyons. The incident pulse is amplified at the crest of mountains and at the upper corners of canyons. The magnitude of amplification is a function of the steepness of the topographic structure and can increase by 50 % compared to a flat surface under the same conditions. The maximum attenuation computed at the bottom of a canyon was 25 %. It can be concluded that the influence of prominent topographic features on the incident P-pulse is similar to that on incident SH waves, which was computed in previous investigations.
ARK: https://n2t.net/ark:/88439/y066050
Permalink: https://geophysicsjournal.com/article/279
Article Details
Authors who publish with this journal as of Vol. 63 agree to the following terms:
a. Authors share the copyright with this journal in equal parts (50% to the journal, 50% to the lead author), and grant the journal right of first publication, with the work after publication simultaneously licensed under Creative Commons Attribution License CC BY-NC-ND 4.0 that allows others to share the work with an acknowledgment of the work's authorship and initial publication in this journal.
b. Authors may enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial publication in this journal, and a reference to this copyright notice.
c. Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) during the submission process, as this can lead to productive exchanges and earlier and greater citation of published work and better sales of the copyright.
Author Self-archiving
Authors retain copyright and grant the Journal of Geophysics right of first publication, with the work three years after publication simultaneously licensed under the Creative Commons BY-NC-ND 4.0 License that allows others to share the work (with an acknowledgment of the work's authorship and initial publication in this journal), except for commercial purposes and for creating derivatives.
Authors can enter into separate, additional, but non-commercial contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository, but not publish it in a book), with an acknowledgment of its initial publication in this journal.
Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) before and during the submission process, as that can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
Additional Notes
This journal is one of a handful of scholarly journals that publish original scientific works under CC BY-NC-ND 4.0 - the only Creative Commons license affording the authors' intellectual property absolute worldwide protection.
Journal of Geophysics is published under the scholar-publishers model, meaning authors do not surrender their copyright to us. Instead, and unlike corporate publishers like Elsevier or Springer Nature that resell copyright to third-parties for up to $80,000 (per paper, per transaction!), the Journal of Geophysics authors share copyright equally with this journal.
Therefore, all the proceeds from reselling copyright to third parties get shared to equal parts (50% to the journal, 50% to the lead author). Under the Berne Convention, this protection is an inheritable right that lasts for as long as the rightsholder lives + 50 years.
By submitting to this journal, the lead author, on behalf of all co-authors, grants permission to this journal to represent all co-authors in negotiating copyright sales and collecting proceeds. The lead author should negotiate with his/her co-authors the modalities of distributing the lead author's portion of the proceeds. Usually, this is per pre-agreed percentage of each co-author's contribution to creating the copyrighted work. (more...)
References
Alterman, Z.S., Loewenthal, D. (1970) Seismic waves in a quarter and three quarter plane. Geophys. J. 20:101-126
Alterman, Z.S., Nathaniel, R. (1975) Seismic waves in a wedge. Bull. Seism. Soc. Am. 65:1697-1719
Boore, D.M. (1972a) Finite-difference methods for seismic-wave propagation in heterogeneous materials. In: Methods in Computational Physics, Vol. 11, Chapter 5. Academic Press, New York
Boore, D.M. (1972b) A note on the effect of simple topography on seismic SH waves. Bull. Seism. Soc. Am. 62, pp. 275-284
Boore, D.M. (1973) The effect of simple topography on seismic waves. Implications for the accelerations recorded at Pacoima Dam, San Fernando Valley, California. Bull. Seism. Soc. Am. 63:1603-1609
Bouchon, M. (1973) Effect of topography on surface motion. Bull. Seism. Soc. Am. 63:615-632
Browning, G., Kreiss, H.O., Oliger, J. (1973) Mesh Refinement. Math. Comp. 27:29-39
Davis, L.L., West, L.R. (1973) Observed effects of topography on ground motion. Bull. Seism. Soc. Am. 63:283-298
Ilan, A., Ungar, A., Alterman, Z. (1975) An improved representation of boundary conditions in finitedifference schemes for seismological problems. Geophys. J. 43:727-746
Ilan, A., Loewenthal, D. (1976) Instability of finite-difference schemes due to boundary conditions in elastic media. Geophysical Prospecting 24:431-453
Reimer, R.B., Clough, R.W., Raphael, J.M. (1974) Seismic response of Pacoima Dam in San Fernando Earthquake. Proc. World Conf. Earthquake Eng. 5th, Rome 2, pp. 2328-2337
Richtmyer, R.D., Morton, K.W. (1967) Difference methods for initial value problems. Interscience, New York-LondonSydney
Trifunac, M.D. (1973) Scattering of plane SH waves by a semicylindrical canyon. Intern. J. Earthquake Eng. Struct. Dyn. 1:267-281
Trifunac, M.D., Hudson, D.E. (1971) Analysis of the Pacoima Dam accelerogram, San Fernando. California, earthquake of 1971. Bull. Seism. Soc. Am. 61:1393-1411
Wong, H.L., Jennings, P.C. (1975) Effects of canyon topography on strong ground motion. Bull. Seism. Soc. Am. 65, 5, pp.1239-1257
Wong, H.L., Trifunac, M.D. (1974) Scattering of plane SH waves by semielliptical canyon. Intern. J. Earthquake Eng. Struct. Dyn. V. 3:157-169