Applications of Moment Tensor Solutions to the Assessment of Earthquake Hazard in Canada

2018 ◽  
pp. 307-317
Author(s):  
J. F. Cassidy ◽  
H. Kao ◽  
John Ristau ◽  
A. Bent
Keyword(s):  
Moment Tensor ◽  
Earthquake Hazard

scholarly journals Road to earthquake mitigation: Lesson learnt from the Yogyakarta earthquake 2006

2009 ◽  
Vol 1 (2) ◽  
Author(s):  
Subagyo Pramumijoyo
Keyword(s):  
Aerial Photograph ◽  
Seismic Velocity ◽  
Moment Tensor ◽  
Earthquake Hazard ◽  
National Standard ◽  
Ground Acceleration ◽  
History Of ◽  
The Difference ◽  
Geologic Setting ◽  
Lake Deposits

At early in the morning of May 27, 2006, people of Yogyakarta was stroke by earthquake and mostly heavily damaged building are in lowland or Yogyakarta depression where is occupied by the Young Merapi sediments. The magnitude of earthquake is Mw = 6.2 and USGS rapid moment tensor shows that this earthquake was due to strike-slip fault movement.Seismic history of Yogyakarta area shows that Yogyakarta was stroke by several earthquakes with different epicenter location. At least two earthquakes stroke the area, that is in 1876 and 1943. The damages are similar to the damages of actual earthquake. Yogyakarta depression is mostly covered by Young Merapi sediments that consist of tuff, volcanic ash, breccias, agglomerate and lava with Quaternary in age. The thickness of this sediment is up to 100 m.Our reactive work was to establish firstly zone of damage. For this purpose, we made aerial photograph along the most damaged area. In the same time one of our teams go to the field to measure the cracks, and the other teams to observe liquefaction, hydro geologic measurement, and observation on landslide induce by earthquake. Secondly, we must understand the soil properties and its thickness, because in seismic history it was a similar damage on the same area due to earthquakes however the earthquake epicenters were different. For this purpose we utilize the method of micro-tremors. We also made some drilling until 60 m each, measuring seismic velocity on bore hole, and magneto telluric measurement. We also have helped by Kyushu University in installing micro seismic net work. The research was followed by either undergraduate and graduate students. Fortunately our research was financed by AUN/Seed Net – JICA. Some of the results were published in a book entitled The Yogyakarta Earthquake of May 27, 2006. Another outcome is the Maps of Microzonation and Earthquake Hazard of Bantul Area that dedicated to Bantul people.Based on aerial photograph observation and field observation on Bantul Regency, especially along the Opak River, and to Wonosari to the East, there was no surface ruptures, so there is no fault on surface. Interpretation of aftershock data was showing the difference cluster. There is still open problem in determining either epicenter or aftershock location. The damage building was interpreted as due to its geologic setting, non engineered building, and close to epicenter of earthquake. This heavily damaged building are located on the Young Merapi sediments at Bantul Regency and lake deposits at Gantiwarno and Bayat area where it can amplify the surface seismic wave. It implies that Peak Ground Acceleration according to Indonesian National Standard should be modified in Yogyakarta area.Keywords: Earthquake, seismic, epicenter, micro-tremor, microzonation

Stress in western Canada from regional moment tensor analysis

2007 ◽  
Vol 44 (2) ◽  
pp. 127-148 ◽  
Author(s):  
John Ristau ◽  
Garry C Rogers ◽  
John F Cassidy
Keyword(s):  
Hazard Analysis ◽  
Moment Tensor ◽  
Puget Sound ◽  
Earthquake Hazard ◽  
Border Region ◽  
Western Canada ◽  
Stress Regime ◽  
Queen Charlotte Islands ◽  
Stress Direction ◽  
East West

More than 180 regional moment tensor (RMT) solutions for moderate-sized earthquakes (M ≥ 4) are used to examine the contemporary stress regime of western Canada and provide valuable information relating to earthquake hazard analysis. The overall regional stress pattern shows mainly NE–SW-oriented P axes for most of western Canada with local variations. In the northern cordillera, the maximum compressive stress direction (σ1) varies from east–west to north–south to NE–SW from south to north. The stress direction σ1 is consistent with the P axis direction for the largest earthquakes, except in the central and northern Mackenzie Mountains where there is a 16° difference. The Yakutat collision zone shows a steady change in σ1 from east–west in the east to north–south in the west. In the Canada – United States border region, RMT solutions suggest a north–south compressional regime may extend through southern British Columbia and northern Washington to the eastern Cordillera. In the Vancouver Island – Puget Sound region, RMT solutions do not show any obvious pattern in faulting style. However, the stress results are consistent with margin-parallel compression in the crust and downdip tension in the subducting slab. Along the Queen Charlotte fault σ1 is oriented ~45° to the strike of the northern section of the fault, which is dominated by strike-slip faulting, and ~60° to the strike of the southern section, which is dominated by high-angle thrust faults. The amount of thrust faulting infers a significant amount of convergence between the Pacific and North America plates in the southern Queen Charlotte Islands region.

Seismic Moment Tensor Screening on the Hypersphere

2019 ◽  
Author(s):  
Sean R. Ford ◽  
Gordon D. Kraft
Keyword(s):  
Seismic Moment ◽  
Moment Tensor ◽  
Seismic Moment Tensor

CHIMP - A SHAKING DATASET TO ASSESS THE PERFORMANCE OF EARTHQUAKE HAZARD MAPS FOR CALIFORNIA

2019 ◽  
Author(s):  
Molly M. Gallahue ◽  
◽  
Leah Salditch ◽  
Susan Hough ◽  
Seth Stein ◽  
...  
Keyword(s):  
Earthquake Hazard ◽  
Hazard Maps

scholarly journals A finite difference method for the static limit analysis of masonry domes under seismic loads

Meccanica ◽  
2021 ◽  
Author(s):  
Nicola A. Nodargi ◽  
Paolo Bisegna
Keyword(s):  
Stress State ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Limit Analysis ◽  
Difference Method ◽  
Moment Tensor ◽  
Static Limit ◽  
Shear Response ◽  
Masonry Domes ◽  
Seismic Forces

AbstractThe static limit analysis of axially symmetric masonry domes subject to pseudo-static seismic forces is addressed. The stress state in the dome is represented by the shell stress resultants (normal-force tensor, bending-moment tensor, and shear-force vector) on the dome mid-surface. The classical differential equilibrium equations of shells are resorted to for imposing the equilibrium of the dome. Heyman’s assumptions of infinite compressive and vanishing tensile strength, alongside with cohesive-frictional shear response, are adopted for imposing the admissibility of the stress state. A finite difference method is proposed for the numerical discretization of the problem, based on the use of two staggered rectangular grids in the parameter space generating the dome mid-surface. The resulting discrete static limit analysis problem results to be a second-order cone programming problem, to be effectively solved by available convex optimization softwares. In addition to a convergence analysis, numerical simulations are presented, dealing with the parametric analysis of the collapse capacity under seismic forces of spherical and ogival domes with parameterized geometry. In particular, the influence that the shear response of masonry material and the distribution of horizontal forces along the height of the dome have on the collapse capacity is explored. The obtained results, that are new in the literature, show the computational merit of the proposed method, and quantitatively shed light on the seismic resistance of masonry domes.

A displacement-dependent moment tensor method for simulating fault-slip induced seismicity

2021 ◽  
Vol 7 (3) ◽  
Author(s):  
Qingsheng Bai ◽  
Heinz Konietzky ◽  
Ziwei Ding ◽  
Wu Cai ◽  
Cun Zhang
Keyword(s):  
Induced Seismicity ◽  
Moment Tensor ◽  
Fault Slip ◽  
Tensor Method

scholarly journals Seismicity, focal mechanism, and stress tensor analysis of the Simav region, western Turkey

2020 ◽  
Vol 12 (1) ◽  
pp. 479-490
Author(s):  
Ahu Kömeç Mutlu
Keyword(s):  
Moment Tensor ◽  
Aftershock Sequence ◽  
Movement Direction ◽  
Normal Faults ◽  
Normal Faulting ◽  
Stress Inversion ◽  
Western Turkey ◽  
Stress Orientations ◽  
Extension Direction ◽  
Inversion Analysis

AbstractThis study focuses on the seismicity and stress inversion analysis of the Simav region in western Turkey. The latest moderate-size earthquake was recorded on May 19, 2011 (Mw 5.9), with a dense aftershock sequence of more than 5,000 earthquakes in 6 months. Between 2004 and 2018, data from earthquake events with magnitudes greater than 0.7 were compiled from 86 seismic stations. The source mechanism of 54 earthquakes with moment magnitudes greater than 3.5 was derived by using a moment tensor inversion. Normal faults with oblique-slip motions are dominant being compatible with the NE-SW extension direction of western Turkey. The regional stress field is assessed from focal mechanisms. Vertically oriented maximum compressional stress (σ1) is consistent with the extensional regime in the region. The σ1 and σ3 stress axes suggest the WNW-ESE compression and the NNE-SSW dilatation. The principal stress orientations support the movement direction of the NE-SW extension consistent with the mainly observed normal faulting motions.

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