Determining whether the worst earthquake has passed

Brodsky, E. E.

doi:10.1038/d41586-019-02972-z

Cited by 8 publications

(6 citation statements)

References 4 publications

(3 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular, very recently, Gulia and Wiemer 31 have shown that the magnitude distribution during aftershock activity is steeper than during foreshock activity. This result is however achieved for only two mainshocks and by means of different selection criterions for the foreshock identification 32 .…”

mentioning

confidence: 98%

The influence of the brittle-ductile transition zone on aftershock and foreshock occurrence

et al. 2020

View full text Add to dashboard Cite

Aftershock occurrence is characterized by scaling behaviors with quite universal exponents. At the same time, deviations from universality have been proposed as a tool to discriminate aftershocks from foreshocks. Here we show that the change in rheological behavior of the crust, from velocity weakening to velocity strengthening, represents a viable mechanism to explain statistical features of both aftershocks and foreshocks. More precisely, we present a model of the seismic fault described as a velocity weakening elastic layer coupled to a velocity strengthening visco-elastic layer. We show that the statistical properties of aftershocks in instrumental catalogs are recovered at a quantitative level, quite independently of the value of model parameters. We also find that large earthquakes are often anticipated by a preparatory phase characterized by the occurrence of foreshocks. Their magnitude distribution is significantly flatter than the aftershock one, in agreement with recent results for forecasting tools based on foreshocks.

show abstract

mentioning

confidence: 98%

The influence of the brittle-ductile transition zone on aftershock and foreshock occurrence

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The example of Central Italy sequence shows that the ND test may provide results which are significantly different from both catalog and test‐based methods, proving that the significance of b ‐value variations depends on the suitability of adopted method. This result opens a new perspective on the debate about the significance of b ‐value variations and, most of all, on the potential of b ‐value variations as an earthquake precursor (Brodsky, 2019; Dascher‐Cousineau et al., 2019; Gulia & Wiemer, 2019; Helmstetter et al, 2003; Hiemer & Kamer, 2015; Mignan, 2014; Wiemer & Wyss, 1997).…”

Section: Discussionmentioning

confidence: 85%

A Normalized Distance Test for Co‐Determining the Completeness Magnitude andb‐Value of Earthquake Catalogs

Lombardi

2021

JGR Solid Earth

View full text Add to dashboard Cite

The quantitative study of the earthquake magnitude distribution started with the publication of what is traditionally referred as "Gutenberg-Richter Law" (GRL; Gutenberg & Richter, 1942; Ishimoto & Iida, 1939), stating the log-linearity of the empirical complementary cumulative distribution of magnitudes. In mathematical terms, the GRL may be described by the equation          10 log N M a b M (1) where a (productivity) and b (slope) are constants and N(M) is the number of events with magnitude equal to or above M. The parameter b represents the ratio of small to large earthquakes: a low b-value describes a data set with a large proportion of larger magnitudes, and vice versa. Following the publication of the GRL, a great amount of studies was carried out, showing a great attention of scientists, which continues to this day. Many of these studies concern some technical problems about the estimation of the b-value, given by the rounding and the uncertainties of magnitudes, the size and the incompleteness of catalogs and the methodologies applied (Bender, 1983; Kamer & Hiemer, 2015; Marzocchi

show abstract

“…The authors claim that the probability of a larger earthquake following a moderate earthquake increases by several orders of magnitude if the b value remains the same or drops significantly rather than increases. However, Brodsky [68] suggested that the observed pattern revealing the changes in b values is a statistical effect rather than deterministic and that researchers need more cases to test this claim.…”

Section: Discussionmentioning

confidence: 99%

The Effect of the Wenchuan and Lushan Earthquakes on the Size Distribution of Earthquakes along the Longmenshan Fault

et al. 2021

View full text Add to dashboard Cite

Changes in the stress state of faults and their surroundings is a highly plausible mechanism explaining earthquake interaction. These stress changes can impact the seismicity rate and the size distribution of earthquakes. However, the effect of large earthquakes on the earthquake size distribution along the Longmenshan fault has not been quantified. We evaluated the levels of the b value for the stable state before and after the large earthquakes on 12 May 2008 (Wenchuan, MS 8.0) and 20 April 2013 (Lushan, MS 7.0) along the Longmenshan fault. We found that after the mainshocks, the size distribution of the subsequent earthquakes shifted toward relatively larger events in the Wenchuan aftershock zone (b value decreased from 1.21 to 0.84), and generally remained invariable in the Lushan aftershock zone (b value remained at 0.76). The time required for the b value to return to stable states after both mainshocks was entirely consistent with the time needed by the aftershock depth images to stop visibly changing. The result of the temporal variation of b values shows decreasing trends for the b value before both large earthquakes. Our results are available for assessing the potential seismic risk of the Longmenshan fault as a reference.

show abstract

Determining whether the worst earthquake has passed

Cited by 8 publications

References 4 publications

The influence of the brittle-ductile transition zone on aftershock and foreshock occurrence

The influence of the brittle-ductile transition zone on aftershock and foreshock occurrence

A Normalized Distance Test for Co‐Determining the Completeness Magnitude andb‐Value of Earthquake Catalogs

The Effect of the Wenchuan and Lushan Earthquakes on the Size Distribution of Earthquakes along the Longmenshan Fault

Contact Info

Product

Resources

About