Options
Tape, Carl
Loading...
4 results
Now showing 1 - 4 of 4
- PublicationOpen AccessRapid Estimation of Damage to Tall Buildings Using Near Real-Time Earthquake and Archived Structural SimulationsThis article outlines a new approach to rapidly estimate the damage to tall buildings immediately following a large earthquake. The preevent groundwork involves the creation of a database of structural responses to a suite of idealized ground‐motion waveforms. The postevent action involves (1) rapid generation of an earthquake source model, (2) near real‐time simulation of the earthquake using a regional spectral‐element model of the earth and computing synthetic seismograms at tall building sites, and (3) estimation of tall building response (and damage) by determining the best‐fitting idealized waveforms to the synthetically generated ground motion at the site and directly extracting structural response metrics from the database. Here, ground‐velocity waveforms are parameterized using sawtoothlike wave trains with a characteristic period (T), amplitude (peak ground velocity, PGV), and duration (number of cycles, N). The proof‐of‐concept is established using the case study of one tall building model. Nonlinear analyses are performed on the model subjected to the idealized wave trains, with T varying from 0.5 s to 6.0 s, PGV varying from 0.125 m/s, and N varying from 1 to 5. Databases of peak transient and residual interstory drift ratios (IDR), and permanent roof drift are created. We demonstrate the effectiveness of the rapid response approach by applying it to synthetic waveforms from a simulated 1857‐like magnitude 7.9 San Andreas earthquake. The peak IDR, a key measure of structural performance, is predicted well enough for emergency response decision making.
82 98 - PublicationOpen AccessBreaking the Adriatic Plate: Adjoint 3D Tomography for the Italian Lithosphere(2021-12-13)
; ; ; ; ; ; ; ; ; ; ; ; ;; ; ;; ; ;The evolution and state of geological structure at Earth’s surface is best understood with an accurate characterization of the subsurface. We present high-resolution seismic tomographic images of tectonic and geological structures of the Italian lithosphere. Enhanced accuracy is enabled by state-of-the-art methods, including three-dimensional wavefield simulations in combination with an adjoint-state method. The procedure iteratively improves an initial 3D traveltime tomography model of the region using full waveforms from 163 earthquakes recorded by 412 stations. Model Im25, resulting from 25 iterations, characterizes the subsurface structure in terms of compressional and shear wavespeeds at a resolution corresponding to a minimum period ~10 s. We discuss three primary findings of Im25 model: a) images of the lithospheric structure in Central Italy highlight the role of fluids and gas (CO2) and their correlation with seismicity, b) images of Southern Italy illuminates the plumbing system of Mt. Etna volcano, c) images of the Adriatic plate explore its complex lithosphere and tectonic evolution.82 20 - PublicationOpen AccessAdjoint tomography of the Italian lithosphere(2023-04)
; ; ; ; ; ; ; ; ; ; ; ; ;; ; ;; ; ; The evolution and state of geological structure at Earth’s surface is best understood with an accurate characterization of the subsurface, where fluid distribution plays a key role. We present high-resolution seismic tomographic images of tectonic and geological features of the Italian lithosphere based on ground motion recordings and obtained through an iterative procedure. Enhanced accuracy is enabled by state-of-the-art three-dimensional wavefield simulations in combination with an adjoint-state method. The resulting tomographic model characterizes the subsurface structure in terms of compressional and shear wavespeed values at remarkable resolution, corresponding to a minimum period of ~10 s. As primary findings of our work, images of the lithospheric structure in Central Italy are consistent with recent studies on the distribution of fluids and gas (CO2) within the Italian subsurface, allowing us to infer the presence of deep melted material that induces shallow gas fluxes, or traps and deep storage of gas that can be correlated with seismicity. We illuminate Mt. Etna volcano and support the hypothesis of a deep reservoir (~30 km) feeding an intermediate-depth magma-filled intrusive body, which in turn is connected to a shallow chamber. We also investigate the intriguing features of the Adriatic plate offshore of the eastern Italian coast. Tomographic evidence reveals a structure of the plate made of two distinct microplates with different fabric and behavior, and separated by the Gargano deformation zone, indicating a complex lithosphere and tectonic evolution.33 4 - PublicationOpen AccessAdjoint Tomography of the Italian Lithosphere(2022)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The evolution and state of geological structure at Earth's surface is best understood with an accurate characterization of the subsurface. Here we present seismic tomographic images of the Italian lithosphere based on ground motion recordings and characterized by compressional and shear wavespeed structure at remarkable resolution, corresponding to a minimum period of ∼10 s. Enhanced accuracy is enabled by state-of-the-art three-dimensional wavefield simulations in combination with an adjoint-state method. We focus on three primary findings of our model Im25. It highlights the distribution of fluids and gas (CO2) within the Italian subsurface and their correlation with seismicity. It illuminates Mt. Etna volcano and supports the hypothesis of a deep reservoir (∼30 km) feeding a shallower magma-filled intrusive body. Offshore of the eastern Italian coast, it reveals that the Adriatic plate is made of two distinct microplates, separated by the Gargano deformation zone, indicating a complex lithosphere and tectonic evolution.449 47