Macroseismic intensity prediction equations for Vrancea intermediate-depth seismic source

2015 ◽  
Vol 79 (3) ◽  
pp. 2005-2031 ◽  
Author(s):  
Radu Văcăreanu ◽  
Mihail Iancovici ◽  
Cristian Neagu ◽  
Florin Pavel
Keyword(s):  
Seismic Source ◽  
Macroseismic Intensity ◽  
Prediction Equations ◽  
Intermediate Depth ◽  
Intensity Prediction

Estimating the accuracy of source “parameters”

1967 ◽  
Vol 57 (3) ◽  
pp. 373-379 ◽  
Author(s):  
Helen W. Freedman
Keyword(s):  
Standard Error ◽  
Source Parameters ◽  
Seismic Source ◽  
Origin Time ◽  
Intermediate Depth ◽  
Seismic Source Parameters ◽  
Space And Time

abstract This paper suggests a method for estimating the errors accompanying estimates of seismic source parameters. While the method is a general one, the data here are from 1962 and 1963 and special attention is given to a few regions, such as the Kuriles. The overall standard error of about one-half a degree in each coordinate and four seconds in origin time are broken down and analyzed in terms of magnitude, depth, and location in space and time. The most accurately located earthquakes appear to be those of intermediate depth and magnitude in highly seismic areas. There is some indication that these errors are decreasing with time.

Evaluation of Intensity Prediction Equations (IPEs) for Small-Magnitude Earthquakes

2021 ◽  
Author(s):  
Ganyu Teng ◽  
Jack W. Baker ◽  
David J. Wald
Keyword(s):  
United States ◽  
Ground Truth ◽  
Site Amplification ◽  
Eastern United States ◽  
Prediction Equations ◽  
Small Magnitude ◽  
Intensity Prediction ◽  
Central United States ◽  
Hazard Disaggregation

Abstract This study assesses existing intensity prediction equations (IPEs) for small unspecified magnitude (M ≤3.5) earthquakes at short hypocentral distances (Dh) and explores such earthquakes’ contribution to the felt shaking hazard. In particular, we consider IPEs by Atkinson and Wald (2007) and Atkinson et al. (2014), and evaluate their performance based on “Did You Feel It” (DYFI) reports and recorded peak ground velocities (PGVs) in the central United States. Both IPEs were developed based on DYFI reports in the central and eastern United States with moment magnitudes above Mw 3.0. DYFI reports are often used as the ground truth when evaluating and developing IPEs, but they could be less reliable when there are limited responses for small-magnitude earthquakes. We first compare the DYFI reports with intensities interpolated from recorded PGVs. Results suggest a minimal discrepancy between the two when the intensity is large enough to be felt (i.e., M >2 and Dh<15  km). We then compare intensities from 31,617 DYFI reports of 3049 earthquakes with the two IPEs. Results suggest that both the IPEs match well with observed intensities for 2.0< M <3.0 and Dh<10  km, but the IPE by Atkinson et al. (2014) matches better for larger distances. We also observe that intensities from DYFI reports attenuate faster compared with the two IPEs, especially for distances greater than 10 km. We then group DYFI reports by inferred VS30 as a proxy for site amplification effects. We observe that intensities at sites with VS30 around 300 m/s are consistently higher than at sites with VS30 around 700 m/s and are also closer to the two IPEs. Finally, we conduct hazard disaggregation for earthquakes at close distances (Dh=7.5  km) using the observed records. Results suggest that earthquakes with magnitudes below M 3.0 contribute more than 40% to the occurrence of felt shaking.

Intensity Prediction Equations for North America

2014 ◽  
Vol 104 (6) ◽  
pp. 3084-3093 ◽  
Author(s):  
G. M. Atkinson ◽  
C. B. Worden ◽  
D. J. Wald
Keyword(s):  
North America ◽  
Prediction Equations ◽  
Intensity Prediction

Aftershock Activity at Intermediate-Depth Earthquakes in Northern Chile Controlled by Plate Hydration

2020 ◽  
Author(s):  
Leoncio Cabrera ◽  
Sergio Ruiz ◽  
Piero Poli ◽  
Eduardo Contreras-Reyes ◽  
Renzo Mancini ◽  
...  
Keyword(s):  
Template Matching ◽  
Broad Band ◽  
Strong Motion ◽  
Seismic Source ◽  
Northern Chile ◽  
Aftershock Activity ◽  
Study Region ◽  
Abrupt Decrease ◽  
Intermediate Depth ◽  
The Impact

<p>We investigate the differences of the seismic source and aftershock activity using kinematic inversions and template matching respectively, for the six largest intraslab intermediate-depth earthquakes occurred in northern Chile (Mw ~6.3) since 2010 at depths between 90 and 130 km and recorded by dense strong-motion and broad-band seismic networks. In addition, we developed a thermal model using the finite element method in the study region with the aim of analyze the impact of temperature on seismic behavior as the oceanic plate subducts. Our results show that geometries of rupture zones are similar, with semi-axis for an elliptical patch approach about 5 km, and stress drop values between 7 and 30 MPa. On the other hand, the number of aftershocks exhibits clear differences, and their amount decreases with increasing the depth within the slab bounded by the 450 ºC isotherm, which represents a limit between a high-hydrated and a dry or low-hydrated region. Furthermore, mainshocks occur at distances from the top of the slab from 7 to 40 km, and all of them exhibit normal focal mechanisms suggesting that the extensional regimen deepens within the slab to the 700-750 ºC isotherm-depth. We suggest that in northern Chile the abrupt decrease of aftershocks in the lower part of the extensional regimen is caused by the absence of a hydrated slab at those depths.</p>

Ground-motion prediction equations for the intermediate depth Vrancea (Romania) earthquakes

2008 ◽  
Vol 6 (3) ◽  
pp. 367-388 ◽  
Author(s):  
Vladimir Sokolov ◽  
Klaus-Peter Bonjer ◽  
Friedemann Wenzel ◽  
Bogdan Grecu ◽  
Mircea Radulian
Keyword(s):  
Ground Motion ◽  
Motion Prediction ◽  
Ground Motion Prediction Equations ◽  
Prediction Equations ◽  
Ground Motion Prediction ◽  
Intermediate Depth

scholarly journals On the Effect of Synthetic and Real Data Properties on Seismic Intensity Prediction Equations

2019 ◽  
Vol 176 (10) ◽  
pp. 4261-4275
Author(s):  
Roman N. Vakarchuk ◽  
Päivi Mäntyniemi ◽  
Ruben E. Tatevossian
Keyword(s):  
Real Data ◽  
Seismic Intensity ◽  
Prediction Equations ◽  
Intensity Prediction

The intermediate earthquake source near Bucaramanga, Colombia

1970 ◽  
Vol 60 (1) ◽  
pp. 269-276 ◽  
Author(s):  
Eysteinn Tryggvason ◽  
James Edwards Lawson
Keyword(s):  
Point Source ◽  
Seismic Source ◽  
Earthquake Source ◽  
Intermediate Depth ◽  
Intermediate Earthquake ◽  
Large Earthquakes ◽  
Frequency Magnitude

abstract An intensive source of intermediate depth earthquakes has been located in northern Colombia. The activity of this source increased significantly between 1956 and 1966, but appears to be decreasing after 1966. The frequency-magnitude relation of the Bucaramanga earthquakes is anomalous, with fewer large earthquakes than expected. The distribution of determined hypocenters is the same as would be observed if all earthquakes originated in the same point source. Therefore it is concluded that the Bucaramanga seismic source consists of a volume, less than 10 km in radius, centered at 6.8°N, 73.1°W., and 150 km depth.

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