Synthetic Hybrid Broadband Seismograms Based on InSAR Coseismic Displacements

2014 ◽  
Vol 104 (6) ◽  
pp. 2735-2754 ◽  
Author(s):  
C. Fortuno ◽  
J. C. de la Llera ◽  
C. W. Wicks ◽  
J. A. Abell
Keyword(s):  
Broadband Seismograms

The Morgan Hill Earthquake of April 24, 1984—The 1.29g Acceleration at Coyote Lake Dam: Due to Directivity, a Double Event, or Both?

1985 ◽  
Vol 1 (3) ◽  
pp. 445-455 ◽  
Author(s):  
Norman A. Abrahamson ◽  
Robert B. Darragh
Keyword(s):  
Spatial Variation ◽  
High Frequency ◽  
Seismic Source ◽  
Fault Rupture ◽  
Constructive Interference ◽  
Ground Acceleration ◽  
Field Station ◽  
S Waves ◽  
Broadband Seismograms ◽  
Double Event

The 1984 Halls Valley (Morgan Hill, California) earthquake had a complex seismic source. Velocities of the major seismic phases measured from continuous broadband seismograms at Berkeley Seismographic Station (BKS) and Richmond Field Station (RFS) show unambiguously that the earthquake is predominantly a double event with the second source hypocenter located approximately 17 km southeast of the mainshock hypocenter given by Bolt, Uhrhammer and Darragh (1985). The southeasterly fault rupture of the first source and the location of the focus of the second source have critical implications for the observed spatial variation of the recorded accelerograms. Of particular engineering interest, the high frequency 1.29g pulse of horizontal ground acceleration measured at Coyote Lake dam can be explained primarily as due to the second source and constructive interference of the principal S waves from the two sources.

scholarly journals Three-dimensional shear wave structure beneath the Philippine Sea from land and ocean bottom broadband seismograms

2006 ◽  
Vol 111 (B6) ◽  
pp. n/a-n/a ◽  
Author(s):  
Takehi Isse ◽  
Kazunori Yoshizawa ◽  
Hajime Shiobara ◽  
Masanao Shinohara ◽  
Kazuo Nakahigashi ◽  
...  
Keyword(s):  
Shear Wave ◽  
Three Dimensional ◽  
Wave Structure ◽  
Ocean Bottom ◽  
Philippine Sea ◽  
Broadband Seismograms

scholarly journals Automatic seismic event recognition and later phase identification for broadband seismograms

1996 ◽  
Vol 86 (6) ◽  
pp. 1896-1909
Author(s):  
Cheng Tong ◽  
Brian L. N. Kennett
Keyword(s):  
Real Time ◽  
Seismic Event ◽  
Expert Knowledge ◽  
Epicentral Distance ◽  
Event Recognition ◽  
Phase Identification ◽  
Classification Problems ◽  
Real Time Analysis ◽  
Single Station ◽  
Broadband Seismograms

Abstract Knowledge of the patterns of frequently observed seismic phases associated with specific distances and depths have been well developed and applied by seismologists (see, e.g., Richter, 1958; Kulhánek, 1990). However, up till now, the expertise of recognizing seismic event patterns for teleseisms has not been translated into automatic processing procedure. A new approach is developed to automate this kind of heuristic human expertise in order to provide a means of improving preliminary event locations from a single site. An automatic interpretation system exploiting three-component broadband seismograms is used to recognize the pattern of seismic arrivals associated with the presence of a seismic event in real time accompanied by an identification of the individual phases. For a single station, such a real-time analysis can be used to provide a preliminary estimation of the location of the event. The inputs to the interpretation process are a set of features for detected phases produced by another real-time phase analyzer. The combinations of these features are investigated using a novel approach to the construction of an expert system. The automatic system exploits expert information to test likely assumptions about phase character and hence epicentral distance and depth. Some hypotheses about the nature of the event will be rejected as implausible, and for the remainder, an assessment is given of the likelihood of the interpretation based on the fit to the character of all available information. This event-recognition procedure provides an effective and feasible means of interprating events at all distances, and characterizing information between hundreds of different possible classes of patterns even when the observation is incomplete. The procedure is based on “assumption trees” and provides a useful tool for classification problems in which a number of factors have to be identified. The control set of expert knowledge used in testing hypotheses is maintained separately from the computational algorithm used in the assumption search; in consequence, the information base can be readily updated.

Source characteristics and dynamics of the October 2018 Baige landslide revealed by broadband seismograms

Landslides ◽  
2019 ◽  
Vol 16 (4) ◽  
pp. 777-785 ◽  
Author(s):  
Zhen Zhang ◽  
Siming He ◽  
Wei Liu ◽  
Heng Liang ◽  
Shuaixing Yan ◽  
...  
Keyword(s):  
Source Characteristics ◽  
Broadband Seismograms

Seismic shaking scenarios for city of Zagreb, Croatia

2021 ◽  
Author(s):  
Helena Latečki ◽  
Josip Stipčević ◽  
Irene Molinari
Keyword(s):  
Goodness Of Fit ◽  
Synthetic Data ◽  
Low Frequency ◽  
Peak Ground Velocity ◽  
Hybrid Technique ◽  
Epicentral Area ◽  
Area Of Interest ◽  
Dense Grid ◽  
Broadband Seismograms ◽  
Zagreb Area

<p>In order to assess the seismic shaking levels, following the strong Zagreb March 22nd 2020 earthquake, we compute broadband seismograms using a hybrid technique. In a hybrid technique, low frequency (LF, f < 1 Hz) and high frequency (HF, f = 1–10 Hz) seismograms are obtained separately and then merged into a single time series. The LF part of seismogram is computed using a deterministic approach while for the HF part, we adopt the semi-stochastic method following the work of Graves and Pitarka (2010). For the purposes of the simulation, we also assemble the 3D velocity and density model of the crust for the city of Zagreb and its surrounding region. The model consists of a detailed description of the main geologic structures that are observed in the upper crust and is embedded within a greater regional EPCrust crustal model (Molinari and Morelli, 2011). To test and evaluate its performance, we apply the hybrid technique to the Zagreb March 22nd 2020 Mw = 5.3 event and four smaller (3.0 < Mw < 5.0) events. We compare the measured seismograms with the synthetic data and validate our results by assessing the goodness of fit for the peak ground velocity values and the shaking duration. Furthermore, since the 1880 Mw = 6.2 historic earthquake significantly contributes to the hazard assessment for the wider Zagreb area, we compute synthetic seismograms for this event at two different hypocenter locations. We calculate broadband waveforms on a dense grid of points and from these we plot the shakemaps to determine if the main expected ground-motion features are well-represented by our approach. Lastly, due to the events that occured in the Petrinja epicentral area at the end of 2020, we decided to extend our 3D model to cover the area of interest. We will present the preliminary results of the simulation for the December 29th 2020 Mw = 6.4 strong earthquake, as well as our plans for further research.</p>

Global Stacking of Broadband Seismograms

1996 ◽  
Vol 67 (4) ◽  
pp. 8-18 ◽  
Author(s):  
L. Astiz ◽  
P. Earle ◽  
P. Shearer
Keyword(s):  
Broadband Seismograms
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