New Hebrides trench: subduction rate from associated lithospheric bulge

1977 ◽  
Vol 14 (2) ◽  
pp. 250-255 ◽  
Author(s):  
J. Dubois ◽  
J. Launay ◽  
J. Recy ◽  
J. Marshall
Keyword(s):  
Outer Wall ◽  
Free Edge ◽  
Uplift Rate ◽  
Topographic Profile ◽  
New Hebrides ◽  
Seismic Strain ◽  
Strain Release ◽  
The Difference ◽  
Seismic Strain Release ◽  
Subduction Rate

We present new data on the lithospheric bulge in the vicinity of the Loyalty and New Hebrides Islands, and attempt to interpret the difference of the topographic profile of the outer wall of the New Hebrides trench from a theoretical profile. The free edge of the lithospheric plate appears to correspond to a line of maximum seismic strain release. The uplift rate and consequently the subduction rate have been calculated from studies of the dynamic aspect of the bulge and from 230Th/234U ages of raised coral terraces.

scholarly journals Some characteristics of the seismicity of the Tyrrhenian Sea Region

2010 ◽  
Vol 27 (1-2) ◽  
Author(s):  
S. MESZAROS ◽  
P. HEDERVARI
Keyword(s):  
South America ◽  
Elastic Strain ◽  
Seismic Events ◽  
Tyrrhenian Sea ◽  
Seismic Belt ◽  
Maximum Value ◽  
Seismic Strain ◽  
Strain Release ◽  
Seismic Strain Release ◽  
Global Tectonics

In the first p a r t of the paper the seismic strain release of the T y r r h e n i a n Sea Region (including Italy), as the function of time, is examined on the basis of t h e d a t a of the e a r t h q u a k e s t h a t took place f r om 1901.01.01 to 1970.12.31, between the northern l a t i t u d e s of 34° and 44° and between the eastern longitudes of 8° and 18.5°, respectively. All registered shocks with a R i c h t e r - m a g n i t u d e of 5.5 or over it were considered, i n d e p e n d e n t l y f r om t h e focal d e p t h . Three periods were recognized in the a c t i v i t y ; t h e lengths of which are not t h e same, however. I n the second p a r t the elastic strain release in accordance with the focal d e p t h of t h e same e a r t h q u a k e s is t r e a t e d briefly. It was found t h at t h e t o t a l strain-release had a maximum value in t h e depth between 0 and 74 kms and there was a minimum between the depth of 300 and 524 kins with an interval between 375 and 449 kms within which no earthquakes occurred at all. The general p a t t e r n of the d i s t r i b u t i o n of seismicity as t h e f u n c t i o n of hypocentral d e p t h reminds to the well-known picture, one can experience in other regions where i n t e r m e d i a t e and deep shocks occur. This s t a t e m e n t is consistent w i t h t h e idea, according to which t h e seismicity of t h e Tyrrhenian Sea Region can be discussed and explained in t h e light of t h e theory of new global tectonics. F i n a l l y , in the t h i r d p a r t of the study, the authors have s t a t e d t h at in some cases multiple events occurred b e n e a t h t h e Tyrrhenian Sea Region. Such multiple seismic events were detected in the case of other areas, such as the Fiji-Tonga-Kermadec Region, the seismic belt of South America etc., — but, according to the knowledge of t h e authors, this is t h e first occasion when multiple seismic events are demonstrated in the Tyrrhenian Sea Region.

Seismic strain release along the Middle America Trench, Mexico

1982 ◽  
Vol 9 (3) ◽  
pp. 182-185 ◽  
Author(s):  
Shi-Chen Wang ◽  
Karen C. McNally ◽  
Robert J. Geller
Keyword(s):  
Middle America Trench ◽  
Middle America ◽  
Seismic Strain ◽  
Strain Release ◽  
Seismic Strain Release

Seismic strain release in the Mexican subduction thrust

1989 ◽  
Vol 58 (4) ◽  
pp. 307-322 ◽  
Author(s):  
John G. Anderson ◽  
Shri Krishna Singh ◽  
J.M. Espindola ◽  
J. Yamamoto
Keyword(s):  
Seismic Strain ◽  
Strain Release ◽  
Seismic Strain Release

Time–Space Evolution of Seismic Strain Release in the Area Shocked by the August 24–October 30 Central Italy Seismic Sequence

2017 ◽  
Vol 174 (5) ◽  
pp. 1875-1887 ◽  
Author(s):  
Simone Barani ◽  
Claudia Mascandola ◽  
Enrico Serpelloni ◽  
Gabriele Ferretti ◽  
Marco Massa ◽  
...  
Keyword(s):  
Central Italy ◽  
Seismic Sequence ◽  
Time Space ◽  
Seismic Strain ◽  
Strain Release ◽  
Seismic Strain Release

The source scaling of swarm-genic slow slip events

2020 ◽  
Author(s):  
Luigi Passarelli ◽  
Eleonora Rivalta ◽  
Paul Antony Selvadurai ◽  
Sigurjón Jónsson
Keyword(s):  
Subduction Zones ◽  
Volcanic Tremor ◽  
Slow Slip ◽  
Aseismic Slip ◽  
Slow Slip Events ◽  
Seismic Strain ◽  
Source Scaling ◽  
Strain Release ◽  
Seismic Strain Release ◽  
Seismic Moment Release

<p>Slow slip events (SSEs) are slow fault ruptures that do not excite detectable seismic waves although they are often accompanied by some forms of seismic strain release, e.g., clusters of low- and very-low frequency earthquakes, and/or episodic or continuous non-volcanic tremor (i.e. tremor-genic SSEs) and earthquake swarms (swarm-genic SSEs). At subduction zones, increasing evidence indicates that aseismic slip and seismic strain release in the form of non-volcanic tremor represent the evolution of slow fracturing. In addition, aseismic slip rate modulates the release of seismic slip during tremor-genic SSEs. No general agreement has been reached, however, on whether source duration-moment scaling of SSEs is linear or follows that of ordinary earthquakes (cubic). To date, investigations on the source scaling has been based on global compilations of tremor-genic SSEs while no studies have looked into the source scaling of swarm-genic SSEs.</p><p>We present the first compilation of source parameters of swarm-genic slow slip events occurring in subduction zones as well as in extensional, transform and volcanic environments. We find for swarm-genic SSEs a power-law scaling of aseismic to seismic moment release during episodes of slow slip that is independent of the tectonic setting. The earthquake productivity, i.e., the ratio of seismic to aseismic moment released, of shallow SSEs is on average higher than that of deeper ones and scales inversely with rupture velocity. The inferred source scaling indicates a strong interplay between the evolution of aseismic slip and the associated seismic response of the host medium and that swarm-genic SSEs and tremor-genic SSEs arise from similar fracturing mechanisms. Depth dependent rheological conditions modulated by fluid pore pressure, temperature and density of asperities appear to be the main controls on the scaling. Large SSEs have systematically high earthquake productivity suggesting static stress transfer as an additional factor in triggering swarms of ordinary earthquakes. Our data suggest that during the slow slip evolution the proportion of seismic strain release is always smaller than the aseismic part although transient changes in stress and fault rheology imparted by swarm-genic SSEs can lead to delayed triggering of major and devastating earthquakes like in the Tohoku, Iquique and L’Aquila cases. The evidence of source scaling reported here will help constraining theoretical models of SSEs rupture propagation and seismic hazard assessments that should take into account the new scaling between aseismic and seismic moment release. </p>

Spatial and temporal constancy of seismic strain release along an evolving segment of the Pacific–North America plate boundary

2011 ◽  
Vol 304 (3-4) ◽  
pp. 565-576 ◽  
Author(s):  
Kurt L. Frankel ◽  
James F. Dolan ◽  
Lewis A. Owen ◽  
Plamen Ganev ◽  
Robert C. Finkel
Keyword(s):  
North America ◽  
Plate Boundary ◽  
The Pacific ◽  
Seismic Strain ◽  
Strain Release ◽  
Seismic Strain Release

Interfacial Fracture Strength of Micro-Scale Si/Cu Components with Different Free-Edge Shape

2015 ◽  
Vol 665 ◽  
pp. 169-172
Author(s):  
Yoshimasa Takahashi ◽  
Hikaru Kondo ◽  
Kazuya Aihara ◽  
Masanori Takuma ◽  
Kenichi Saitoh ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Stress Singularity ◽  
Fracture Initiation ◽  
Interfacial Fracture ◽  
Free Edge ◽  
Stress Distributions ◽  
Micro Scale ◽  
Transmission Electron ◽  
The Difference

The strength against interfacial fracture initiation from a free-edge of Si/Cu micro-components was evaluated. The micro-scale cantilever specimens containing dissimilar interfaces were fabricated with a focused-ion-beam (FIB) technique, and they were loaded with a quantitative nanoindenter holder operated in a transmission electron microscope (TEM). The specimens were successfully fractured along the Si/Cu interface, and the critical loads at fracture were measured. The critical stress distribution near the free-edge was evaluated with the finite element method (FEM). The near-edge stress distributions of 90°/90°-shaped specimens were scattered while those of 135°/135°-shaped specimens were in good agreement despite the difference in specimen dimensions. Such a difference was discussed in terms of the relation between the magnitude of stress singularity and the microstructures of material.

The modulus of elasticity of equine hoof wall: implications for the mechanical function of the hoof.

1996 ◽  
Vol 199 (8) ◽  
pp. 1829-1836 ◽  
Author(s):  
J E Douglas ◽  
C Mittal ◽  
J J Thomason ◽  
J C Jofriet
Keyword(s):  
Moisture Content ◽  
Modulus Of Elasticity ◽  
Weight Bearing ◽  
Outer Wall ◽  
Wall Material ◽  
Detectable Effect ◽  
Dorsal Wall ◽  
The Mean ◽  
The Difference ◽  
Equine Hoof

During normal weight-bearing and locomotion, the equine hoof wall deforms in a consistent pattern; the proximal dorsal wall rotates caudo-ventrally about the distal dorsal border and there is latero-medial flaring posteriorly. The aim of this study is to examine whether there are regional differences in the modulus of elasticity of hoof wall material and whether such differences correlate with the pattern of deformation which occurs in vivo. The modulus of elasticity of equine hoof wall was determined in tension and compression for samples from six forefeet. Samples were tested at the mid-point of the inner and outer halves of the wall thickness at two positions along the proximo-distal axis of the dorsal wall, and from the mid-point of its thickness at the lateral and medial quarters. Test samples were oriented both parallel and perpendicular to the tubules that characterise the microstructure of the wall. The colour of each sample was noted, and the moisture content measured. The range in the mean modulus of elasticity for all samples and tests was 460-1049 MPa, the dorsal outer wall having the highest values, the dorsal inner wall the lowest, and the quarters having intermediate values. The mean value obtained for the quarters was similar to the average of the values for the dorsal inner and outer walls. At all sites, the modulus of elasticity was marginally higher in compression than in tension, possibly owing to microstructural defects. The difference in stiffness between the outer wall and the inner wall was inversely related to moisture content. The difference in stiffness between the dorsal outer and inner walls demonstrates that the equine hoof wall has a comparatively rigid external capsule with a lining of lower stiffness. This arrangement presumably provides some stress protection to the internally adjacent living tissues. The similarity in stiffness between the samples from the quarters and the mean of the two dorsal wall sites suggests that the wall at the quarters has a similar change in stiffness across its thickness as the dorsal wall. However, the reduced thickness of the wall at the quarters compared with the dorsal wall means that, functionally, the quarters are more flexible than the dorsal wall. This will facilitate the flaring of the lateral and medial walls which occurs during weight-bearing. Anisotropy was evident only in tensile tests of the dorsal wall samples. Contrary to popular assertions that white hooves are mechanically inferior, horn pigmentation had no detectable effect on stiffness.

Sign in / Sign up

Export Citation Format

Share Document