Research Article| December 11, 2018 Shallow Ambient‐Noise 3D Tomography in the Concepción Basin, Chile: Implications for Low‐Frequency Ground Motions Diego A. Inzunza; Diego A. Inzunza aDepartamento de Ingeniería Civil, Universidad de Concepción, Víctor Lamas 1290, Casilla 160‐C, Correo 3, 4070409 Concepción, Chile, diegoinzunza@udec.cl Search for other works by this author on: GSW Google Scholar Gonzalo A. Montalva; Gonzalo A. Montalva bDepartamento de Ingeniería Civil, Universidad de Concepción, Edmundo Larenas 219, Casilla 160‐C, Correo 3, 4070409 Concepción, Chile, gmontalva@udec.cl Search for other works by this author on: GSW Google Scholar Felipe Leyton; Felipe Leyton cCentro Sismológico National, University of Chile, Blanco Encalada 2002, Casilla #2777, 8370415 Santiago, Chile, leyton@csn.uchile.cl Search for other works by this author on: GSW Google Scholar German Prieto; German Prieto dGeosciences Department, National University of Colombia, Carrera 30 #45‐03, 111321 Bogotá, Colombia, gaprietogo@unal.edu.co Search for other works by this author on: GSW Google Scholar Sergio Ruiz Sergio Ruiz eGeophysics Department, University of Chile, Blanco Encalada 2002, Casilla #2777, 8370415 Santiago, Chile, sruiz@dgf.uchile.cl Search for other works by this author on: GSW Google Scholar Author and Article Information Diego A. Inzunza aDepartamento de Ingeniería Civil, Universidad de Concepción, Víctor Lamas 1290, Casilla 160‐C, Correo 3, 4070409 Concepción, Chile, diegoinzunza@udec.cl Gonzalo A. Montalva bDepartamento de Ingeniería Civil, Universidad de Concepción, Edmundo Larenas 219, Casilla 160‐C, Correo 3, 4070409 Concepción, Chile, gmontalva@udec.cl Felipe Leyton cCentro Sismológico National, University of Chile, Blanco Encalada 2002, Casilla #2777, 8370415 Santiago, Chile, leyton@csn.uchile.cl German Prieto dGeosciences Department, National University of Colombia, Carrera 30 #45‐03, 111321 Bogotá, Colombia, gaprietogo@unal.edu.co Sergio Ruiz eGeophysics Department, University of Chile, Blanco Encalada 2002, Casilla #2777, 8370415 Santiago, Chile, sruiz@dgf.uchile.cl Publisher: Seismological Society of America First Online: 11 Dec 2018 Online Issn: 1943-3573 Print Issn: 0037-1106 © Seismological Society of America Bulletin of the Seismological Society of America (2019) 109 (1): 75–86. https://doi.org/10.1785/0120180061 Article history First Online: 11 Dec 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Diego A. Inzunza, Gonzalo A. Montalva, Felipe Leyton, German Prieto, Sergio Ruiz; Shallow Ambient‐Noise 3D Tomography in the Concepción Basin, Chile: Implications for Low‐Frequency Ground Motions. Bulletin of the Seismological Society of America 2018;; 109 (1): 75–86. doi: https://doi.org/10.1785/0120180061 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of the Seismological Society of America Search Advanced Search Abstract Forecasting surface seismic intensities is the main objective of much of the research in seismic engineering. The seismic demand for tall buildings, bridges, wind farms, and other existing slender structures is predominantly at low frequencies, but these structures are usually outside the range of the design spectra prescribed by codes. This article presents a 3D tomography model of the Concepción basin, Chile, where the shear‐wave velocity structure is estimated to 500‐m depth. The maximum basin thickness is approximately 160 m, but the average is about 100 m. The underlying bedrock is composed of two different units. The interface between the two bedrock units, at a depth of about 460 m, causes a low‐frequency resonance at 0.5 Hz. The two bedrock units have shear‐wave velocities close to 1000 and 3700 m/s⁠, respectively. The resonance in the neighborhood of 0.5 Hz is controlled by the thickness and VS value of the first bedrock unit from roughly 100 to 460 m. This frequency coincides with the surface intensities recorded at the basin during the 2010 Mw 8.8 Maule earthquake. Shear‐wave velocity (⁠VS⁠) tomography models from dispersion curves show heterogeneities in half‐space stiffness that predict the observed differences in low‐frequency (long‐period) ground motions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.