Sean Kamran Ahdi (Former Employee)
Science and Products
Filter Total Items: 19
2021 U.S. National Seismic Hazard Model for the State of Hawaii 2021 U.S. National Seismic Hazard Model for the State of Hawaii
The 2021 U.S. National Seismic Hazard Model (NSHM) for the State of Hawaii updates the two-decades-old former model by incorporating new data and modeling techniques to improve the underlying ground shaking forecasts of tectonic-fault, tectonic-flexure, volcanic, and caldera collapse earthquakes. Two earthquake ground shaking hazard models (public policy and research) are produced that...
Authors
Mark D. Petersen, Allison Shumway, Peter M. Powers, Morgan P. Moschetti, Andrea L. Llenos, Andrew J. Michael, Charles Mueller, Arthur D. Frankel, Sanaz Rezaeian, Kenneth S. Rukstales, Daniel E. McNamara, P. Okubo, Yuehua Zeng, Kishor S. Jaiswal, Sean Kamran Ahdi, Jason M. Altekruse, Brian Shiro
Data resources for NGA-subduction project Data resources for NGA-subduction project
A relational database was developed over a five-year period to support ground motion model (GMM) development for the Next Generation Attenuation-Subduction (NGA-Sub) project. The relational database has components that interact according to a database schema, including a source and path component used to describe attributes of seismic sources in global subduction regions and to compute...
Authors
V. Contreras, S. Mazzoni, T. Kishida, S.K. Ahdi, Robert B. Darragh, R.R. Youngs, B.S.J. Chiou, N. Kuehn, Kathryn Wooddell, Y. Bozorgnia, Jonathan P. Stewart
Horizontal-to-vertical spectral ratios from California sites: Open-source database and data interpretation to establish site parameters Horizontal-to-vertical spectral ratios from California sites: Open-source database and data interpretation to establish site parameters
Frequency-dependent horizontal-to-vertical spectral ratios (HVSR) of Fourier amplitudes from three-component recordings can provide information on one or more site resonant frequencies and relative levels of amplification at those frequencies. Such information is potentially useful for predicting site amplification but is not present in site databases that have been developed over the...
Authors
Pengfei Wang, Paolo Zimmaro, Tatiana Gospe, Sean Kamran Ahdi, Alan Yong, Jonathan P. Stewart
A probabilistic framework to model distributions of VS30 A probabilistic framework to model distributions of VS30
The time‐averaged shear‐wave velocity in the upper 30 m depth from the ground surface, or VS30, is often used as a predictor to describe local site effects in ground‐motion models. Although VS30 is typically determined from in situ measurements, it is not always feasible to obtain such measurements due to project restrictions or site accessibility. This motivates the development and use...
Authors
Utkarsh Mital, Sean K Ahdi, Julie A. Herrick, Junko Iwahashi, Alexandros Savvaidis, Alan Yong
Liquefaction and related ground failure from July 2019 Ridgecrest earthquake sequence Liquefaction and related ground failure from July 2019 Ridgecrest earthquake sequence
The 2019 Ridgecrest earthquake sequence produced a 4 July M 6.5 foreshock and a 5 July M 7.1 mainshock, along with 23 events with magnitudes greater than 4.5 in the 24 hr period following the mainshock. The epicenters of the two principal events were located in the Indian Wells Valley, northwest of Searles Valley near the towns of Ridgecrest, Trona, and Argus. We describe observed...
Authors
Paolo Zimmaro, Chukwuebuka C Nweke, Janis Hernandez, Kenneth S Hudson, Martin B Hudson, Sean K Ahdi, Matt Boggs, Craig A. Davis, Christine A. Goulet, Scott J Brandenberg, Kenneth W. Hudnut, Jonathan P. Stewart
Preliminary report on engineering and geological effects of the July 2019 Ridgecrest earthquake sequence Preliminary report on engineering and geological effects of the July 2019 Ridgecrest earthquake sequence
The Ridgecrest Earthquake sequence included a foreshock event on July 4 2019 (M6.4) and a M7.1 mainshock event on July 5 2019. These events occurred in the Eastern California Shear Zone, near Indian Wells Valley, south of China Lake and west of Searles Valley. GEER has partnered with several organizations to collect perishable data and document the important impacts of these events...
Authors
Scott J Brandenberg, Pengfei Wang, Chukwuebuka C Nweke, Kenneth Hudson, Silvia Mazzoni, Yousef Bozorgnia, Kenneth W. Hudnut, Craig A. Davis, Sean K Ahdi, Farzin Zareian, Jawad Fayaz, Richard D Koehler, Colin Chupik, Ian Pierce, Alana Williams, Sinan Akciz, Martin B Hudson, Tadahiro Kishida, Benjamin A. Brooks, Ryan D. Gold, Daniel J. Ponti, Katherine M. Scharer, Devin McPhillips, Christopher DuRoss, Todd Ericksen, Janis Hernandez, Jay Patton, Brian Olson, Timothy E. Dawson, Jerome Treiman, Kelly Blake, Jeffrey Buchhuber, Chris L M Madugo, Joseph Sun, Andrea Donnellan, Greg Lyzenga, Erik Conway
A proposed seismic velocity profile database model A proposed seismic velocity profile database model
We describe the data model that we intend to use in a publicly available site profile database under development for the United States. The initial implementation of the database contains data from California. Currently, our prototype data model consists of JavaScript Object Notation (JSON) format files for storing metadata and data. For a site to be included in the database, the minimum...
Authors
Shamsher Sadiq, Okan Ilkan, Sean K Ahdi, Yousef Bozorgina, Youssef M.A. Hashash, Dong Youp Kwak, Duhee Park, Alan Yong, Jonathan P. Stewart
Science and Products
Filter Total Items: 19
2021 U.S. National Seismic Hazard Model for the State of Hawaii 2021 U.S. National Seismic Hazard Model for the State of Hawaii
The 2021 U.S. National Seismic Hazard Model (NSHM) for the State of Hawaii updates the two-decades-old former model by incorporating new data and modeling techniques to improve the underlying ground shaking forecasts of tectonic-fault, tectonic-flexure, volcanic, and caldera collapse earthquakes. Two earthquake ground shaking hazard models (public policy and research) are produced that...
Authors
Mark D. Petersen, Allison Shumway, Peter M. Powers, Morgan P. Moschetti, Andrea L. Llenos, Andrew J. Michael, Charles Mueller, Arthur D. Frankel, Sanaz Rezaeian, Kenneth S. Rukstales, Daniel E. McNamara, P. Okubo, Yuehua Zeng, Kishor S. Jaiswal, Sean Kamran Ahdi, Jason M. Altekruse, Brian Shiro
Data resources for NGA-subduction project Data resources for NGA-subduction project
A relational database was developed over a five-year period to support ground motion model (GMM) development for the Next Generation Attenuation-Subduction (NGA-Sub) project. The relational database has components that interact according to a database schema, including a source and path component used to describe attributes of seismic sources in global subduction regions and to compute...
Authors
V. Contreras, S. Mazzoni, T. Kishida, S.K. Ahdi, Robert B. Darragh, R.R. Youngs, B.S.J. Chiou, N. Kuehn, Kathryn Wooddell, Y. Bozorgnia, Jonathan P. Stewart
Horizontal-to-vertical spectral ratios from California sites: Open-source database and data interpretation to establish site parameters Horizontal-to-vertical spectral ratios from California sites: Open-source database and data interpretation to establish site parameters
Frequency-dependent horizontal-to-vertical spectral ratios (HVSR) of Fourier amplitudes from three-component recordings can provide information on one or more site resonant frequencies and relative levels of amplification at those frequencies. Such information is potentially useful for predicting site amplification but is not present in site databases that have been developed over the...
Authors
Pengfei Wang, Paolo Zimmaro, Tatiana Gospe, Sean Kamran Ahdi, Alan Yong, Jonathan P. Stewart
A probabilistic framework to model distributions of VS30 A probabilistic framework to model distributions of VS30
The time‐averaged shear‐wave velocity in the upper 30 m depth from the ground surface, or VS30, is often used as a predictor to describe local site effects in ground‐motion models. Although VS30 is typically determined from in situ measurements, it is not always feasible to obtain such measurements due to project restrictions or site accessibility. This motivates the development and use...
Authors
Utkarsh Mital, Sean K Ahdi, Julie A. Herrick, Junko Iwahashi, Alexandros Savvaidis, Alan Yong
Liquefaction and related ground failure from July 2019 Ridgecrest earthquake sequence Liquefaction and related ground failure from July 2019 Ridgecrest earthquake sequence
The 2019 Ridgecrest earthquake sequence produced a 4 July M 6.5 foreshock and a 5 July M 7.1 mainshock, along with 23 events with magnitudes greater than 4.5 in the 24 hr period following the mainshock. The epicenters of the two principal events were located in the Indian Wells Valley, northwest of Searles Valley near the towns of Ridgecrest, Trona, and Argus. We describe observed...
Authors
Paolo Zimmaro, Chukwuebuka C Nweke, Janis Hernandez, Kenneth S Hudson, Martin B Hudson, Sean K Ahdi, Matt Boggs, Craig A. Davis, Christine A. Goulet, Scott J Brandenberg, Kenneth W. Hudnut, Jonathan P. Stewart
Preliminary report on engineering and geological effects of the July 2019 Ridgecrest earthquake sequence Preliminary report on engineering and geological effects of the July 2019 Ridgecrest earthquake sequence
The Ridgecrest Earthquake sequence included a foreshock event on July 4 2019 (M6.4) and a M7.1 mainshock event on July 5 2019. These events occurred in the Eastern California Shear Zone, near Indian Wells Valley, south of China Lake and west of Searles Valley. GEER has partnered with several organizations to collect perishable data and document the important impacts of these events...
Authors
Scott J Brandenberg, Pengfei Wang, Chukwuebuka C Nweke, Kenneth Hudson, Silvia Mazzoni, Yousef Bozorgnia, Kenneth W. Hudnut, Craig A. Davis, Sean K Ahdi, Farzin Zareian, Jawad Fayaz, Richard D Koehler, Colin Chupik, Ian Pierce, Alana Williams, Sinan Akciz, Martin B Hudson, Tadahiro Kishida, Benjamin A. Brooks, Ryan D. Gold, Daniel J. Ponti, Katherine M. Scharer, Devin McPhillips, Christopher DuRoss, Todd Ericksen, Janis Hernandez, Jay Patton, Brian Olson, Timothy E. Dawson, Jerome Treiman, Kelly Blake, Jeffrey Buchhuber, Chris L M Madugo, Joseph Sun, Andrea Donnellan, Greg Lyzenga, Erik Conway
A proposed seismic velocity profile database model A proposed seismic velocity profile database model
We describe the data model that we intend to use in a publicly available site profile database under development for the United States. The initial implementation of the database contains data from California. Currently, our prototype data model consists of JavaScript Object Notation (JSON) format files for storing metadata and data. For a site to be included in the database, the minimum...
Authors
Shamsher Sadiq, Okan Ilkan, Sean K Ahdi, Yousef Bozorgina, Youssef M.A. Hashash, Dong Youp Kwak, Duhee Park, Alan Yong, Jonathan P. Stewart