scholarly journals Ground Shaking and Seismic Source Spectra for Large Earthquakes around the Megathrust Fault Offshore of Northeastern Honshu, Japan

2013 ◽  
Vol 103 (2B) ◽  
pp. 1221-1241 ◽  
Author(s):  
L. Ye ◽  
T. Lay ◽  
H. Kanamori
Keyword(s):  
Seismic Source ◽  
Ground Shaking ◽  
Source Spectra ◽  
Large Earthquakes

Potential Losses in a Repeat of the 1886 Charleston, South Carolina, Earthquake

2005 ◽  
Vol 21 (4) ◽  
pp. 1157-1184 ◽  
Author(s):  
Ivan Wong ◽  
Jawhar Bouabid ◽  
William Graf ◽  
Charles Huyck ◽  
Allan Porush ◽  
...  
Keyword(s):  
South Carolina ◽  
Public Awareness ◽  
Seismic Source ◽  
The State ◽  
Earthquake Risk ◽  
Loss Assessment ◽  
Ground Shaking ◽  
Earthquake Scenarios ◽  
Earthquake Losses ◽  
Fire Stations

A comprehensive earthquake loss assessment for the state of South Carolina using HAZUS was performed considering four different earthquake scenarios: a moment magnitude ( M) 7.3 “1886 Charleston-like” earthquake, M 6.3 and M 5.3 events also from the Charleston seismic source, and an M 5.0 earthquake in Columbia. Primary objectives of this study were (1) to generate credible earthquake losses to provide a baseline for coordination, capability development, training, and strategic planning for the South Carolina Emergency Management Division, and (2) to raise public awareness of the significant earthquake risk in the state. Ground shaking, liquefaction, and earthquake-induced landsliding hazards were characterized using region-specific inputs on seismic source, path, and site effects, and ground motion numerical modeling. Default inventory data on buildings and facilities in HAZUS were either substantially enhanced or replaced. Losses were estimated using a high resolution 2- km×2- km grid rather than the census tract approach used in HAZUS. The results of the loss assessment indicate that a future repeat of the 1886 earthquake would be catastrophic, resulting in possibly 900 deaths, more than 44,000 injuries, and a total economic loss of $20 billion in South Carolina alone. Schools, hospitals, fire stations, ordinary buildings, and bridges will suffer significant damage due to the general lack of seismic design in the state. Lesser damage and losses will be sustained in the other earthquake scenarios although even the smallest event could result in significant losses.

scholarly journals Seismic source spectra and estimated stress drop derived from cohesive-zone models of circular subshear rupture

2014 ◽  
Vol 197 (2) ◽  
pp. 1002-1015 ◽  
Author(s):  
Y. Kaneko ◽  
P. M. Shearer
Keyword(s):  
Stress Drop ◽  
Cohesive Zone ◽  
Seismic Source ◽  
Cohesive Zone Models ◽  
Source Spectra

A theorem for the direct estimation of seismic source spectra

1997 ◽  
Vol 269 (3-4) ◽  
pp. 337-341
Author(s):  
Z.L. Wu ◽  
S.G. Kim ◽  
Y.T. Chen
Keyword(s):  
Seismic Source ◽  
Direct Estimation ◽  
Source Spectra

scholarly journals Machine learning of source spectra for large earthquakes

2021 ◽  
Author(s):  
Shang Ma ◽  
Zefeng Li ◽  
Wei Wang
Keyword(s):  
Machine Learning ◽  
Source Spectra ◽  
Large Earthquakes

Precariously balanced rocks and ground-motion maps for Southern California

1996 ◽  
Vol 86 (1A) ◽  
pp. 43-54 ◽  
Author(s):  
James N. Brune
Keyword(s):  
Ground Motion ◽  
Power Plants ◽  
Southern California ◽  
Time History ◽  
High Energy ◽  
Fault Creep ◽  
Rock Outcrops ◽  
Ground Shaking ◽  
Slow Earthquakes ◽  
Large Earthquakes

Abstract Groups of precariously balanced rocks are effectively low-resolution strong-motion seismoscopes that have been operating on solid rock outcrops for thousands of years and, once the methodology has been developed, can provide important information about seismic risk. In one zone, near Victorville, only 30 km from the nearest point on the San Andreas fault, more than 50 precarious rocks have been documented. Widespread rock varnish suggests that many of these rocks have been in their current unstable positions for thousands of years. We have established the mechanical basis for rough estimates of the horizontal accelerations necessary to topple these rocks, using field observations and numerical and physical modeling. To verify that zones of precarious rocks do not occur near historic earthquakes, searches using binoculars were made along roads, with occasional foot surveys, near large earthquakes. Based on these reconnaissance searches, we conclude that no precarious rock zones are found within 15 km of zones of high-energy release of historic large earthquakes. To document the occurrence of precarious rocks in southern California, road surveys were carried out along major roads. Four zones of precarious rocks and seven other zones of somewhat less precarious rocks have been documented. Published probabilistic ground-motion maps for southern California are compared with the occurrence of zones of precarious and semi-precarious rocks. The results are encouraging and suggest that eventually, studies of precarious rocks will provide important constraints on the assumptions on which the maps are based. Results from studies of precarious rocks may eventually provide important information for siting and design of sensitive structures such as hospitals and power plants. Precarious rocks give a direct indication of past ground shaking, in contrast to the indirect inference provided by fault-trenching studies, which may be subject to uncertainties in the actual time history of slip due to the fault (e.g., fault creep, “slow” earthquakes, or unknown dynamic stress drop). It is concluded that precarious rocks warrant further study and quantitative analysis.

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.

scholarly journals Prediction of the area affected by earthquake-induced landsliding based on seismological parameters

2017 ◽  
Vol 17 (7) ◽  
pp. 1159-1175 ◽  
Author(s):  
Odin Marc ◽  
Patrick Meunier ◽  
Niels Hovius
Keyword(s):  
Scaling Laws ◽  
Seismic Energy ◽  
Seismic Source ◽  
Distribution Area ◽  
Rupture Directivity ◽  
Source Depth ◽  
Landslide Area ◽  
Earthquake Parameters ◽  
Ground Shaking ◽  
Landslide Distribution

Abstract. We present an analytical, seismologically consistent expression for the surface area of the region within which most landslides triggered by an earthquake are located (landslide distribution area). This expression is based on scaling laws relating seismic moment, source depth, and focal mechanism with ground shaking and fault rupture length and assumes a globally constant threshold of acceleration for onset of systematic mass wasting. The seismological assumptions are identical to those recently used to propose a seismologically consistent expression for the total volume and area of landslides triggered by an earthquake. To test the accuracy of the model we gathered geophysical information and estimates of the landslide distribution area for 83 earthquakes. To reduce uncertainties and inconsistencies in the estimation of the landslide distribution area, we propose an objective definition based on the shortest distance from the seismic wave emission line containing 95 % of the total landslide area. Without any empirical calibration the model explains 56 % of the variance in our dataset, and predicts 35 to 49 out of 83 cases within a factor of 2, depending on how we account for uncertainties on the seismic source depth. For most cases with comprehensive landslide inventories we show that our prediction compares well with the smallest region around the fault containing 95 % of the total landslide area. Aspects ignored by the model that could explain the residuals include local variations of the threshold of acceleration and processes modulating the surface ground shaking, such as the distribution of seismic energy release on the fault plane, the dynamic stress drop, and rupture directivity. Nevertheless, its simplicity and first-order accuracy suggest that the model can yield plausible and useful estimates of the landslide distribution area in near-real time, with earthquake parameters issued by standard detection routines.

Regional seismic risk in British Columbia — damage and loss distribution in Victoria and Vancouver

2005 ◽  
Vol 32 (2) ◽  
pp. 361-371 ◽  
Author(s):  
Tuna Onur ◽  
Carlos E Ventura ◽  
W.D Liam Finn
Keyword(s):  
British Columbia ◽  
Seismic Risk ◽  
Seismic Source ◽  
Economic Loss ◽  
Block Basis ◽  
Loss Distribution ◽  
Ground Shaking ◽  
High Rise ◽  
Two Cities ◽  
Different Types

This paper presents the results of regional seismic risk assessment studies that were carried out for two cities in southwestern British Columbia, Vancouver and Victoria. Ground shaking intensity in the area was obtained using the seismic source zones delineated by the Geological Survey of Canada for a probability level of 10% chance of exceedance in 50 years. Building inventories were compiled by aggregating data from sidewalk surveys as well as municipal databases. Modified Mercalli intensity-based damage matrices that relate the level of ground shaking to the amount of damage expected in different types of structures were used to estimate damage to structural and non-structural components of buildings. Estimated damage and loss distributions were mapped on a block-by-block basis. The historic sections of the cities were estimated to have damage levels between 10% and 30% of the replacement cost, while in the rest of the cities the estimated damage was generally in the 5% to 10% range. The results show the estimated economic loss distribution is considerably different from the damage distribution. Although the older neighbourhoods of the cities are expected to suffer highest amount of damage, the highest amount of economic loss is estimated to occur in areas with concentration of concrete high-rise buildings.Key words: seismic hazard, seismic risk, vulnerability, earthquake, damage, loss, probability, modified Mercalli intensity.

scholarly journals Precursory worldwide signatures of earthquake occurrences on Swarm satellite data

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
A. De Santis ◽  
D. Marchetti ◽  
F. J. Pavón-Carrasco ◽  
G. Cianchini ◽  
L. Perrone ◽  
...  
Keyword(s):  
Electron Density ◽  
Warning System ◽  
Seismic Source ◽  
Statistical Correlation ◽  
Earthquake Magnitude ◽  
Time Interval ◽  
Preparation Phase ◽  
Whole Space ◽  
Swarm Satellite ◽  
Large Earthquakes

AbstractThe study of the preparation phase of large earthquakes is essential to understand the physical processes involved, and potentially useful also to develop a future reliable short-term warning system. Here we analyse electron density and magnetic field data measured by Swarm three-satellite constellation for 4.7 years, to look for possible in-situ ionospheric precursors of large earthquakes to study the interactions between the lithosphere and the above atmosphere and ionosphere, in what is called the Lithosphere-Atmosphere-Ionosphere Coupling (LAIC). We define these anomalies statistically in the whole space-time interval of interest and use a Worldwide Statistical Correlation (WSC) analysis through a superposed epoch approach to study the possible relation with the earthquakes. We find some clear concentrations of electron density and magnetic anomalies from more than two months to some days before the earthquake occurrences. Such anomaly clustering is, in general, statistically significant with respect to homogeneous random simulations, supporting a LAIC during the preparation phase of earthquakes. By investigating different earthquake magnitude ranges, not only do we confirm the well-known Rikitake empirical law between ionospheric anomaly precursor time and earthquake magnitude, but we also give more reliability to the seismic source origin for many of the identified anomalies.

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