Frequency–Magnitude Distribution of −3.7 ≤ M W  ≤ 1 Mining-Induced Earthquakes Around a Mining Front and b Value Invariance with Post-Blast Time

2013 ◽  
Vol 171 (10) ◽  
pp. 2665-2684 ◽  
Author(s):  
Makoto Naoi ◽  
Masao Nakatani ◽  
Shigeki Horiuchi ◽  
Yasuo Yabe ◽  
Joachim Philipp ◽  
...  
Keyword(s):  
B Value ◽  
Induced Earthquakes ◽  
Magnitude Distribution ◽  
Mining Front ◽  
Frequency Magnitude Distribution ◽  
Frequency Magnitude

Risk from Oklahoma’s Induced Earthquakes: The Cost of Declustering

2020 ◽  
Author(s):  
Jeremy Maurer ◽  
Deborah Kane ◽  
Marleen Nyst ◽  
Jessica Velasquez
Keyword(s):  
Financial Risk ◽  
B Value ◽  
Earthquake Risk ◽  
Eastern United States ◽  
Induced Earthquakes ◽  
Magnitude Distribution ◽  
Seismicity Rate ◽  
Seismicity Rates ◽  
Tectonic Earthquakes ◽  
Frequency Magnitude

ABSTRACT The U.S. Geological Survey (USGS) has for each year 2016–2018 released a one-year seismic hazard map for the central and eastern United States (CEUS) to address the problem of induced and triggered seismicity (ITS) in the region. ITS in areas with historically low rates of earthquakes provides both challenges and opportunities to learn about crustal conditions, but few scientific studies have considered the financial risk implications of damage caused by ITS. We directly address this issue by modeling earthquake risk in the CEUS using the 1 yr hazard model from the USGS and the RiskLink software package developed by Risk Management Solutions, Inc. We explore the sensitivity of risk to declustering and b-value, and consider whether declustering methods developed for tectonic earthquakes are suitable for ITS. In particular, the Gardner and Knopoff (1974) declustering algorithm has been used in every USGS hazard forecast, including the recent 1 yr forecasts, but leads to the counterintuitive result that earthquake risk in Oklahoma is at its highest level in 2018, even though there were one-fifth as many earthquakes as occurred in 2016. Our analysis shows that this is a result of (1) the peculiar characteristics of the declustering algorithm with space-varying and time-varying seismicity rates, (2) the fact that the frequency–magnitude distribution of earthquakes in Oklahoma is not well described by a single b-value, and (3) at later times, seismicity is more spatially diffuse and seismicity rate increases are closer to more populated areas. ITS in Oklahoma may include a combination of swarm-like events with tectonic-style events, which have different frequency–magnitude and aftershock distributions. New algorithms for hazard estimation need to be developed to account for these unique characteristics of ITS.

Mapping b-Value Anomalies Along the Indonesian Island Chain: Implications for Upcoming Earthquakes

2014 ◽  
Vol 08 (04) ◽  
pp. 1450010 ◽  
Author(s):  
Santi Pailoplee
Keyword(s):  
Spatial Relationship ◽  
B Value ◽  
Fixed Number ◽  
Earthquake Catalogue ◽  
Suitable Assumption ◽  
B Values ◽  
Magnitude Distribution ◽  
Risk Areas ◽  
Frequency Magnitude Distribution ◽  
Frequency Magnitude

In this study, the geospatial frequency–magnitude distribution (FMD) b-value images of the prospect sources of upcoming earthquakes were investigated along the Indonesian Sunda Margin (ISM) that strikes parallel to and near the Indonesian Island chain. After enhancing the completeness and stability of the earthquake catalogue, the seismicity data were separated according to their seismotectonic setting into shallow crustal and Intraslab earthquakes. In order to verify the spatial relationship between the b-values and the occurrence of subsequent major earthquakes, the complete shallow crustal seismicity dataset (1980–2005) was truncated into the 1980–2000 sub-dataset. Utilizing the suitable assumption of fixed-number of earthquakes, retrospective tests of both the complete and truncated datasets supported that areas of comparatively low b-values could reasonably be expected to predict likely hypocenters of future earthquakes. As a result, the present-day distributions of b-values derived from the complete (1980–2005) shallow crustal and Intraslab seismicity datasets revealed eight and six earthquake-prone areas, respectively, along the ISM. Since most of these high risk areas proposed here are quite close to the major cities of Indonesia, attention should be paid and mitigation plans should be developed for both seismic and tsunami hazards.

A grid-based b-value approximation through Southern and Northern Norway: preliminary results 

2021 ◽  
Author(s):  
Rodrigo Estay ◽  
Claudia Pavez
Keyword(s):  
B Value ◽  
Seismic Events ◽  
Online Database ◽  
Magnitude Of Completeness ◽  
Stress Regime ◽  
Magnitude Distribution ◽  
The Mean ◽  
Frequency Magnitude Distribution ◽  
Frequency Magnitude ◽  
Grid Based

<p>The Gutenberg – Richter’s b-value is commonly used to analyze the frequency-magnitude distribution of earthquakes, describing the proportion of small and large seismic events as the first estimation of seismic hazard. Additionally, the b-value has been used as a stress meter, giving some insights into the stress regime in different regions around the world. In this research, a grid-based spatial distribution for the b – value was estimated in three different areas of Norway: northern (74°-81° N/ 12°-26° E), southern (57°-64°N/3°-12° E), and the ridge zones of Mohns and Knipovich. For this, we used a complete catalog from the years 2000 to 2019, which was obtained from the Norwegian National Seismic Network online database. The magnitude of completeness was estimated separately for each zone both in time and space, covering a total area of ~425,000 km<sup>2</sup>. Our results show a regional variation of the mean b-value for northern (b<sub>north</sub> = 0.79) and southern (b<sub>south</sub> = 1.03) Norway, and the Ridge (b<sub>ridge</sub> = 0.73), which can be interpreted in terms of the predominant stress regime in the different zones. So far, a few calculations regarding the b-value were previously done in Norway to analyze local intraplate sequences. Then, according to our knowledge, this research corresponds to the first estimation of a regional spatial variation of the b – value in the country.</p>

scholarly journals The Effect of Declustering on the Size Distribution of Mainshocks

2021 ◽  
Author(s):  
Leila Mizrahi ◽  
Shyam Nandan ◽  
Stefan Wiemer
Keyword(s):  
Seismic Hazard Assessment ◽  
B Value ◽  
Aftershock Sequence ◽  
Earthquake Catalogs ◽  
Magnitude Distribution ◽  
Independent Events ◽  
Potential Source ◽  
Epidemic Type Aftershock Sequence ◽  
Frequency Magnitude Distribution ◽  
Frequency Magnitude

Abstract Declustering aims to divide earthquake catalogs into independent events (mainshocks), and dependent (clustered) events, and is an integral component of many seismicity studies, including seismic hazard assessment. We assess the effect of declustering on the frequency–magnitude distribution of mainshocks. In particular, we examine the dependence of the b-value of declustered catalogs on the choice of declustering approach and algorithm-specific parameters. Using the catalog of earthquakes in California since 1980, we show that the b-value decreases by up to 30% due to declustering with respect to the undeclustered catalog. The extent of the reduction is highly dependent on the declustering method and parameters applied. We then reproduce a similar effect by declustering synthetic earthquake catalogs with known b-value, which have been generated using an epidemic-type aftershock sequence model. Our analysis suggests that the observed decrease in b-value must, at least partially, arise from the application of the declustering algorithm on the catalog, rather than from differences in the nature of mainshocks versus fore- or aftershocks. We conclude that declustering should be considered as a potential source of bias in seismicity and hazard studies.

B-Value Analysis of AE Signal Subjected to Stepwise Loading

2011 ◽  
Vol 403-408 ◽  
pp. 4126-4131 ◽  
Author(s):  
Noorsuhada Md Nor ◽  
Norazura Muhamad Bunnori ◽  
Ibrahim Azmi ◽  
Shahidan Shahiron ◽  
Siti Ramziah Basri ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
B Value ◽  
Assessment Method ◽  
Value Analysis ◽  
Magnitude Distribution ◽  
Ae Signal ◽  
Linear Slope ◽  
Log Linear ◽  
Frequency Magnitude Distribution ◽  
Frequency Magnitude

Acoustic emission is an effective damage assessment method in a structure subjected to mechanical loading. Calculation of log-linear slope of the frequency-magnitude distribution of acoustic emission (known as b-value) has been carried out. It is found that the b-valuefor the log frequency-magnitude graph has a good correlation for beam imposed of stepwise loading.It also can be seen that the b-value is decreased as the load increased.

Magnitudes of induced earthquakes and geometric scales of fluid-stimulated rock volumes

Geophysics ◽  
2011 ◽  
Vol 76 (6) ◽  
pp. WC55-WC63 ◽  
Author(s):  
Serge A. Shapiro ◽  
Oliver S. Krüger ◽  
Carsten Dinske ◽  
Cornelius Langenbruch
Keyword(s):  
Principal Axis ◽  
Hydrocarbon Reservoirs ◽  
Induced Earthquakes ◽  
Large Magnitude ◽  
Magnitude Distribution ◽  
Type Frequency ◽  
Main Factors ◽  
Geometrical Scale ◽  
Frequency Magnitude Distribution ◽  
Frequency Magnitude

Sometimes rock stimulations by fluid injections into geothermal boreholes are able to trigger perceptible or even potentially damaging earthquakes. This does not seem to be the case for hydraulic fracturing of hydrocarbon reservoirs. Reasons for such a difference and factors defining magnitudes of induced earthquakes (triggered tectonicly as well as induced artificially) remain unclear. We analyzed microseismic data obtained by fluid stimulations at different geothermal and hydrocarbon sites. This analysis indicates that a rupture corresponding to a fluid-induced earthquake seems to be only probable along a surface located mainly inside a stimulated rock volume. We approximated the stimulated volume by an ellipsoid, and compared the statistics of induced events with the statistics of randomly distributed thin flat disks modeling rupture surfaces. We found that one of the main factors limiting the probability to induce a large-magnitude event is the minimum principal axis of a fluid-stimulated rock volume. This geometrical scale can be very different in geothermal and hydrocarbon reservoirs. It may control the order of a largest possible magnitude. We quantified an impact of the geometry of a stimulated volume on the Gutenberg-Richter-type frequency-magnitude distribution of induced earthquakes. Our results show that monitoring the spatial growth of seismicity in real time can help to constrain a risk of inducing damaging earthquakes.

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