scholarly journals Measurement of differential rupture duration as constraints on the source finiteness of deep-focus earthquakes: 2. Synthetic tests to estimate errors in rupture vectors and their effect on fault plane identification

2010 ◽  
Vol 115 (B9) ◽  
Author(s):  
Linda M. Warren
Keyword(s):  
Fault Plane ◽  
Deep Focus ◽  
Rupture Duration

The Peru-Bolivia border earthquake of August 15, 1963

1970 ◽  
Vol 60 (2) ◽  
pp. 639-646 ◽  
Author(s):  
Umesh Chandra
Keyword(s):  
Travel Time ◽  
Fault Plane ◽  
P Wave ◽  
Focal Mechanism Solution ◽  
Event Analysis ◽  
Rupture Propagation ◽  
Fault Propagation ◽  
Amplitude Data ◽  
First Motion ◽  
Deep Focus

abstract The seismograms of the deep focus Peru-Bolivia border earthquake of August 15, 1963 reveal the presence of a number of conspicuous phases occurring within 15 seconds of the first P onset. These phases cannot be explained on the basis of known travel-time curves. Accordingly, the earthquake is interpreted to have occurred in a series of jerks during the course of fault propagation, or in other words it is composed of multiple events. Only one of these events, following the first event, at which the amplitude of the recorded motion becomes suddenly very large, has been located in this study. The focal mechanism solution of this earthquake has been determined from the P wave first motion and amplitude data. Consideration of the direction of rupture propagation determined from the multiple event analysis makes it possible to identify the fault plane in the mechanism solution. The parameters of the fault plane, length and speed of rupture between the two events have been determined.

First motions from seismic sources

1960 ◽  
Vol 50 (1) ◽  
pp. 117-134 ◽  
Author(s):  
Leon Knopoff ◽  
Freeman Gilbert
Keyword(s):  
Radiation Pattern ◽  
Fault Plane ◽  
Displacement Vector ◽  
Strain Tensor ◽  
Dislocation Model ◽  
Double Couple ◽  
First Motion ◽  
Sudden Release ◽  
Deep Focus ◽  
Dynamic Dislocation

ABSTRACT An application of dynamic dislocation theory gives the elastodynamic radiation resulting from the sudden occurrence of an earthquake due to faulting. The fault plane is visualized as a geometrical discontinuity across which there exists a sudden discontinuity in either one component of the strain tensor or one component of the displacement vector. It is shown that there are eight independent models, if unilateral faulting is assumed; and an argument is presented to demonstrate the likelihood that unilateral faulting does not exist in nature. For bilateral faulting the eight independent models are reduced in number to five. Of these five, two are more likely to occur in nature than the others. One of these, the displacement dislocation model, has a first-motion radiation pattern formally identical with that of a double couple in an unfaulted medium. The second, the shearstrain dislocation model, has a first-motion radiation pattern formally identical with that of an isolated force in an unfaulted medium. The latter type of mechanism may occur in deep-focus earthquakes. Another type of radiation, corresponding to the single couple in an unfaulted medium, results from the sudden release of shear strain in a laminar region.

An optimal strategy for searching the best fault-plane solution using wave-amplitude data

1977 ◽  
Vol 67 (5) ◽  
pp. 1355-1362
Author(s):  
Kailash Khattri
Keyword(s):  
Seismic Waves ◽  
Fault Plane ◽  
Source Parameters ◽  
P Wave ◽  
Spectral Amplitude ◽  
Fault Plane Solution ◽  
Amplitude Data ◽  
Earthquake Source Parameters ◽  
Plane Solution ◽  
Deep Focus

abstract This paper presents an optimum search procedure known as the Fibonacci Technique for abstracting the earthquake-source parameters from the amplitude data of seismic waves. The power of the method has been demonstrated by determining the fault-plane solution of a deep-focus earthquake using the P-wave spectral amplitude data.

Radiation mode of S waves from a deep-focus earthquake as derived from observations

1963 ◽  
Vol 53 (3) ◽  
pp. 643-659
Author(s):  
Keichi Kasahara
Keyword(s):  
Fault Plane ◽  
Analog Computer ◽  
P Wave ◽  
Wave Form ◽  
Type I ◽  
Radiation Mode ◽  
S Waves ◽  
Plane Solution ◽  
Earthquake Mechanism ◽  
Deep Focus

Abstract Two representative hypotheses on earthquake mechanism (so-called force types I and II) have been examined in comparison with seismograms for the earthquake of February 18, 1956 (south off Honshu, Japan; h = 450 km). On the basis of the fault-plane solution derived from P-wave data, one can predict polarity and relative amplitude of shear wave phases for a given station. The prediction by both of the hypotheses is compared with the observations at Kiruna and several other stations, where the principal seismic phases have been recorded clearly. The comparison has proved that the force type I does not fit the present case. The second type, on the other hand, explains the observations more consistently, although there are minor disagreements with respect to later phases. Reduction of the recorded wave form by an analog computer has shown that the original seismic disturbance (S) from the source is very simple in its wave form and harmonizes very well with Honda's theory. If we accept his theory, the radius of the origin sphere is estimated at 30-40 km for the present case.

scholarly journals Fault plane orientations of intermediate‐depth and deep‐focus earthquakes in the Japan‐Kuril‐Kamchatka subduction zone

2015 ◽  
Vol 120 (12) ◽  
pp. 8366-8382 ◽  
Author(s):  
Linda M. Warren ◽  
Elena C. Baluyut ◽  
Timothy Osburg ◽  
Kristen Lisac ◽  
Siiri Kokkinen
Keyword(s):  
Subduction Zone ◽  
Fault Plane ◽  
Intermediate Depth ◽  
Deep Focus

scholarly journals A holistic seismotectonic model of Delhi region

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brijesh K. Bansal ◽  
Kapil Mohan ◽  
Mithila Verma ◽  
Anup K. Sutar
Keyword(s):  
Strain Energy ◽  
Fault Plane ◽  
Near Field ◽  
Energy Estimates ◽  
The West ◽  
Fault Plane Solutions ◽  
Northern India ◽  
Structural Environment ◽  
Reverse Faulting ◽  
Using Data

AbstractDelhi region in northern India experiences frequent shaking due to both far-field and near-field earthquakes from the Himalayan and local sources, respectively. The recent M3.5 and M3.4 earthquakes of 12th April 2020 and 10th May 2020 respectively in northeast Delhi and M4.4 earthquake of 29th May 2020 near Rohtak (~ 50 km west of Delhi), followed by more than a dozen aftershocks, created panic in this densely populated habitat. The past seismic history and the current activity emphasize the need to revisit the subsurface structural setting and its association with the seismicity of the region. Fault plane solutions are determined using data collected from a dense network in Delhi region. The strain energy released in the last two decades is also estimated to understand the subsurface structural environment. Based on fault plane solutions, together with information obtained from strain energy estimates and the available geophysical and geological studies, it is inferred that the Delhi region is sitting on two contrasting structural environments: reverse faulting in the west and normal faulting in the east, separated by the NE-SW trending Delhi Hardwar Ridge/Mahendragarh-Dehradun Fault (DHR-MDF). The WNW-ESE trending Delhi Sargoda Ridge (DSR), which intersects DHR-MDF in the west, is inferred as a thrust fault. The transfer of stress from the interaction zone of DHR-MDF and DSR to nearby smaller faults could further contribute to the scattered shallow seismicity in Delhi region.

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