On the wobbles of phase-velocity dispersion curves

• Published in: Geophysical Journal International
• Main Authors: Kolinsky P., Bokelmann G., Hetenyi G., Abreu R., Allegretti I., Apoloner M. -T., Aubert C., Besancon S., De Berc M. B., Brunel D., Capello M., Carman M., Cavaliere A., Cheze J., Chiarabba C., Clinton J., Cougoulat G., Crawford W. C., Cristiano L., Czifra T., D'Alema E., Danesi S., Daniel R., Dannowski A., Dasovic I., Deschamps A., Dessa J. -X., Doubre C., Egdorf S., Fiket T., Fischer K., Friederich W., Fuchs F., Funke S., Giardini D., Govoni A., Graczer Z., Groschl G., Heimers S., Heit B., Herak D., Herak M., Huber J., Jaric D., Jedlicka P., Jia Y., Jund H., Kissling E., Klingen S., Klotz B., Kopp H., Korn M., Kotek J., Kuhne L., Kuk K., Lange D., Loos J., Lovati S., Malengros D., Margheriti L., Maron C., Martin X., Massa M., Mazzarini F., Meier T., Metral L., Molinari I., Moretti M., Nardi A., Pahor J., Paul A., Pequegnat C., Petersen D., Pesaresi D., Piccinini D., Piromallo C., Plenefisch T., Plomerova J., Pondrelli S., Prevolnik S., Racine R., Regnier M., Reiss M., Ritter J., Rumpker G., Salimbeni S., Santulin M., Scherer W., Schippkus S., Schulte-Kortnack D., Sipka V., Solarino S., Spallarossa D., Spieker K., Stipcevic J., Strollo A., Sule B., Szanyi G., Szucs E., Thomas C., Thorwart M., Tilmann F., Ueding S., Vallocchia M., Vecsey L., Voigt R., Wassermann J., Weber Z., Weidle C., Wesztergom V., Weyland G., Wiemer S., Wolf F., Wolyniec D., Zieke T., Zivcic M., Zlebcikova H.
• Other Authors: Kolinsky, P., Bokelmann, G., Hetenyi, G., Abreu, R., Allegretti, I., Apoloner, M. -T., Aubert, C., Besancon, S., De Berc, M. B., Brunel, D., Capello, M., Carman, M., Cavaliere, A., Cheze, J., Chiarabba, C., Clinton, J., Cougoulat, G., Crawford, W. C., Cristiano, L., Czifra, T., D'Alema, E., Danesi, S., Daniel, R., Dannowski, A., Dasovic, I., Deschamps, A., Dessa, J. -X., Doubre, C., Egdorf, S., Fiket, T., Fischer, K., Friederich, W., Fuchs, F., Funke, S., Giardini, D., Govoni, A., Graczer, Z., Groschl, G., Heimers, S., Heit, B., Herak, D., Herak, M., Huber, J., Jaric, D., Jedlicka, P., Jia, Y., Jund, H., Kissling, E., Klingen, S., Klotz, B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press 2021
• Subjects: Structure of the Earth; Surface waves and free oscillation; Wave propagation; Wave scattering and diffraction; South Atlantic Ocean
• Online Access: https://hdl.handle.net/11567/1098993; https://doi.org/10.1093/gji/ggaa487

To calculate phase-velocity dispersion curves,we introduce amethodwhich reflects both structural and dynamic effects of wave propagation and interference. Rayleigh-wave fundamentalmode surface waves from the South Atlantic Ocean earthquake of 19 August 2016, M = 7.4, observed at the AlpArray network in Europe are strongly influenced by the upper-mantle lowvelocity zone under the Cameroon Volcanic Line in Central Africa. Predicting phase-delay times affected by diffraction from this heterogeneity for each station gives phase velocities as they would be determined using the classical two-station method as well as the advanced array-beamforming method. Synthetics from these two methods are thus compared with measurements. We show how the dynamic phase velocity differs from the structural phase velocity, howthese differences evolve in space and howtwo-station and arraymeasurements are affected. In principle, arrays are affected with the same uncertainty as the two-station measurements. The dynamic effects can be several times larger than the error caused by the unknown arrival angle in case of the two-station method. The non-planarity of the waves and its relation to the arrival angle and dynamic phase-velocity deviations is discussed. Our study is complemented by extensive review of literature related to the surface wave phase-velocity measurement of the last 120 years.