Limits...
The debate on the prognostic value of earthquake foreshocks: a meta-analysis.

Mignan A - Sci Rep (2014)

Bottom Line: From this literature survey, anomalous foreshocks are found to emerge when m(min) < M - 3.0.These results suggest that a deviation from the normal behaviour of seismicity may be observed only when microseismicity is considered.These results are to be taken with caution since the 37 studies do not all show the same level of reliability.

View Article: PubMed Central - PubMed

Affiliation: Swiss Seismological Service, ETH Zurich, NO H66, Sonneggstrasse 5, CH-8092 Zurich.

ABSTRACT
The hypothesis that earthquake foreshocks have a prognostic value is challenged by simulations of the normal behaviour of seismicity, where no distinction between foreshocks, mainshocks and aftershocks can be made. In the former view, foreshocks are passive tracers of a tectonic preparatory process that yields the mainshock (i.e., loading by aseismic slip) while in the latter, a foreshock is any earthquake that triggers a larger one. Although both processes can coexist, earthquake prediction is plausible in the first case while virtually impossible in the second. Here I present a meta-analysis of 37 foreshock studies published between 1982 and 2013 to show that the justification of one hypothesis or the other depends on the selected magnitude interval between minimum foreshock magnitude m(min) and mainshock magnitude M. From this literature survey, anomalous foreshocks are found to emerge when m(min) < M - 3.0. These results suggest that a deviation from the normal behaviour of seismicity may be observed only when microseismicity is considered. These results are to be taken with caution since the 37 studies do not all show the same level of reliability. These observations should nonetheless encourage new research in earthquake predictability with focus on the potential role of microseismicity.

No MeSH data available.


Related in: MedlinePlus

Other statistics derived from the meta-analysis.a. Differences in methods employed to argue in favour of loading by aseismic slip or in favour of earthquake triggering. Statistical approaches with use of stacking methods (large data set analysis) tend preferentially towards an earthquake triggering origin of foreshocks. Arguments for loading are mostly based on the study of individual foreshock sequences. b. Evolution of thoughts and methods through time. Popularity of the triggering view has increased over time with the development of statistical studies based on stacking methods. Since the 2000's, there is no clear preference for any given theory of foreshock origin, showing that the debate continues.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3924212&req=5

f3: Other statistics derived from the meta-analysis.a. Differences in methods employed to argue in favour of loading by aseismic slip or in favour of earthquake triggering. Statistical approaches with use of stacking methods (large data set analysis) tend preferentially towards an earthquake triggering origin of foreshocks. Arguments for loading are mostly based on the study of individual foreshock sequences. b. Evolution of thoughts and methods through time. Popularity of the triggering view has increased over time with the development of statistical studies based on stacking methods. Since the 2000's, there is no clear preference for any given theory of foreshock origin, showing that the debate continues.

Mentions: Additional trends derived from the meta-analysis (Table S1) are shown in Figure 3. I find that statistical approaches employing stacking methods (large data set analysis) tend preferentially towards an earthquake triggering origin of foreshocks. Arguments for loading are mostly based on the study of individual foreshock sequences (Fig. 3a). Second, when investigating the studies chronologically, I find that the popularity of the triggering view has increased over time in parallel to the development of statistical approaches based on stacking methods. Since the 2000's, there is no clear preference for any given theory of foreshock origin, showing that the debate continues (Fig. 3b).


The debate on the prognostic value of earthquake foreshocks: a meta-analysis.

Mignan A - Sci Rep (2014)

Other statistics derived from the meta-analysis.a. Differences in methods employed to argue in favour of loading by aseismic slip or in favour of earthquake triggering. Statistical approaches with use of stacking methods (large data set analysis) tend preferentially towards an earthquake triggering origin of foreshocks. Arguments for loading are mostly based on the study of individual foreshock sequences. b. Evolution of thoughts and methods through time. Popularity of the triggering view has increased over time with the development of statistical studies based on stacking methods. Since the 2000's, there is no clear preference for any given theory of foreshock origin, showing that the debate continues.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3924212&req=5

f3: Other statistics derived from the meta-analysis.a. Differences in methods employed to argue in favour of loading by aseismic slip or in favour of earthquake triggering. Statistical approaches with use of stacking methods (large data set analysis) tend preferentially towards an earthquake triggering origin of foreshocks. Arguments for loading are mostly based on the study of individual foreshock sequences. b. Evolution of thoughts and methods through time. Popularity of the triggering view has increased over time with the development of statistical studies based on stacking methods. Since the 2000's, there is no clear preference for any given theory of foreshock origin, showing that the debate continues.
Mentions: Additional trends derived from the meta-analysis (Table S1) are shown in Figure 3. I find that statistical approaches employing stacking methods (large data set analysis) tend preferentially towards an earthquake triggering origin of foreshocks. Arguments for loading are mostly based on the study of individual foreshock sequences (Fig. 3a). Second, when investigating the studies chronologically, I find that the popularity of the triggering view has increased over time in parallel to the development of statistical approaches based on stacking methods. Since the 2000's, there is no clear preference for any given theory of foreshock origin, showing that the debate continues (Fig. 3b).

Bottom Line: From this literature survey, anomalous foreshocks are found to emerge when m(min) < M - 3.0.These results suggest that a deviation from the normal behaviour of seismicity may be observed only when microseismicity is considered.These results are to be taken with caution since the 37 studies do not all show the same level of reliability.

View Article: PubMed Central - PubMed

Affiliation: Swiss Seismological Service, ETH Zurich, NO H66, Sonneggstrasse 5, CH-8092 Zurich.

ABSTRACT
The hypothesis that earthquake foreshocks have a prognostic value is challenged by simulations of the normal behaviour of seismicity, where no distinction between foreshocks, mainshocks and aftershocks can be made. In the former view, foreshocks are passive tracers of a tectonic preparatory process that yields the mainshock (i.e., loading by aseismic slip) while in the latter, a foreshock is any earthquake that triggers a larger one. Although both processes can coexist, earthquake prediction is plausible in the first case while virtually impossible in the second. Here I present a meta-analysis of 37 foreshock studies published between 1982 and 2013 to show that the justification of one hypothesis or the other depends on the selected magnitude interval between minimum foreshock magnitude m(min) and mainshock magnitude M. From this literature survey, anomalous foreshocks are found to emerge when m(min) < M - 3.0. These results suggest that a deviation from the normal behaviour of seismicity may be observed only when microseismicity is considered. These results are to be taken with caution since the 37 studies do not all show the same level of reliability. These observations should nonetheless encourage new research in earthquake predictability with focus on the potential role of microseismicity.

No MeSH data available.


Related in: MedlinePlus