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arxiv: 1908.00279 · v25 · submitted 2019-08-01 · ⚛️ physics.geo-ph · cond-mat.stat-mech

Identifying the occurrence time of an impending mainshock: A very recent case

P. A. Varotsos , N. V. Sarlis , E. S. Skordas , M. S. Lazaridou-Varotsos This is my paper

Pith reviewed 2026-05-24 16:25 UTC · model grok-4.3

classification ⚛️ physics.geo-ph cond-mat.stat-mech
keywords natural time analysisseismic electric signalsmainshock timingearthquake precursorscritical pointGreece seismicity
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0 comments X

The pith

Natural time analysis of seismicity after a July SES activity identifies criticality on 15 November morning for the 17 November Mw5.4 mainshock.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper reviews and applies a procedure that uses natural time analysis on seismicity recorded after a precursory Seismic Electric Signals activity to determine when an impending mainshock will occur. In the case of the Mw5.4 event in Greece on 17 November 2014, which was the strongest in the area for over half a century, an SES was recorded on 27 July 2014 and the subsequent analysis showed the system approaching the critical point early on 15 November. A reader would care if this procedure can narrow the occurrence time to within days because the quake was strongly felt in Athens and similar events cause damage in populated regions.

Core claim

After the SES activity recorded on 27 July 2014, natural time analysis of the seismicity in the candidate area reveals that the system approached the critical point early in the morning on 15 November 2014, two days before the Mw5.4 mainshock on 17 November 2014.

What carries the argument

Natural time analysis applied to seismicity following SES activity, which tracks the approach to the critical point marking mainshock occurrence.

If this is right

  • The occurrence time of the mainshock can be narrowed to within two days using this procedure.
  • The method applies even when the event is the strongest in the region for more than fifty years.
  • Additional SES activities recorded recently may indicate other events approaching criticality.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same procedure could be tested on other SES-mainshock pairs in Greece to check consistency of the timing result.
  • If the method holds, combining it with other seismic monitoring might reduce uncertainty in short-term forecasts.
  • Application to different tectonic settings would require verifying that SES precedes mainshocks in those regions as well.

Load-bearing premise

The SES recorded on 27 July 2014 is a true precursor to this specific mainshock and the natural time analysis of later seismicity identifies the critical point without bias from choosing the area or window after the fact.

What would settle it

A future mainshock of similar magnitude occurring in the same area without a preceding SES, or without the natural time analysis showing criticality days in advance, would contradict the timing identification.

Figures

Figures reproduced from arXiv: 1908.00279 by E. S. Skordas, M. S. Lazaridou-Varotsos, N. V. Sarlis, P. A. Varotsos.

Figure 1
Figure 1. Figure 1: FIG. 1: (color online) . (a) The SES activity of dichotomous [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2: How the histograms of Prob( [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3: (color online) The SES activity recorded at KER [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4: The SES activity recorded at KER geolectrical statio [PITH_FULL_IMAGE:figures/full_fig_p004_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5: The SES activity at KER station (raw data) on 8 Decembe [PITH_FULL_IMAGE:figures/full_fig_p005_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6: The same as Figure 2 but after the SES activity at [PITH_FULL_IMAGE:figures/full_fig_p006_6.png] view at source ↗
Figure 10
Figure 10. Figure 10: FIG. 10: The SES activity recorded at KER geolectrical sta [PITH_FULL_IMAGE:figures/full_fig_p007_10.png] view at source ↗
Figure 9
Figure 9. Figure 9: FIG. 9: The same as Figure 2 but after the SES at KER [PITH_FULL_IMAGE:figures/full_fig_p007_9.png] view at source ↗
Figure 11
Figure 11. Figure 11: FIG. 11: The same as Figure 2 but after the SES at KER station on [PITH_FULL_IMAGE:figures/full_fig_p008_11.png] view at source ↗
read the original abstract

The procedure by means of which the occurrence time of an impending mainshock can be identified by analyzing in natural time the seismicity in the candidate area subsequent to the recording of a precursory Seismic Electric Signals (SES) activity is reviewed. Here, we report the application of this procedure to an Mw5.4 mainshock that occurred in Greece on 17 November 2014 and was strongly felt in Athens. This mainshock (which is pretty rare since it is the strongest in that area for more than half a century) was preceded by an SES activity recorded on 27 July 2014 and the results of the natural time analysis reveal that the system approached the critical point (mainshock occurrence) early in the morning on 15 November 2014. SES activities that have been recently recorded are also presented. Furthermore, in a Note we discuss the case of the Mw5.3 earthquake that was also strongly felt in Athens on 19 July 2019 (Parnitha fault).

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper reviews a procedure that uses natural time analysis of seismicity within a candidate area (defined after recording precursory SES activity) to identify the occurrence time of an impending mainshock. It applies the method to the Mw5.4 event of 17 November 2014 in Greece (preceded by SES activity on 27 July 2014), reporting that the system approached criticality early on 15 November 2014. The manuscript also presents recently recorded SES activities and includes a note on the Mw5.3 event of 19 July 2019.

Significance. If the central claim holds after addressing area-selection independence, the work would demonstrate a concrete, falsifiable application of the authors' natural-time-plus-SES framework to a recent, well-documented Greek event, adding to the body of case studies in this approach to short-term forecasting. The result is incremental rather than transformative, as it rests on the same methodology introduced in the authors' prior publications.

major comments (2)
  1. [Abstract] Abstract: the claim that the candidate area was analyzed after the 27 July 2014 SES recording does not specify the a-priori criteria used to delineate the spatial window; without an explicit, pre-mainshock definition of the area boundaries (independent of the 17 November epicenter), the reported approach to criticality on 15 November cannot be evaluated for post-hoc selection bias.
  2. [Abstract] Abstract and Note: the identification of the critical point on 15 November 2014 is presented as the outcome of the natural-time procedure, yet no quantitative values are given for the natural-time parameters (e.g., the exact threshold for the variance of natural time or the entropy measure) or for the number of events analyzed in the candidate area, preventing independent verification of the reported date.
minor comments (2)
  1. The manuscript should include a clear statement of how the candidate area was chosen and whether any time-window restrictions were applied before the mainshock occurred.
  2. Figure captions (if present in the full text) should explicitly label the time series segments used for the natural-time calculation leading to the 15 November identification.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the detailed and constructive report. We address the two major comments point by point below. Both points identify legitimate gaps in the current presentation that we will correct in revision.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the claim that the candidate area was analyzed after the 27 July 2014 SES recording does not specify the a-priori criteria used to delineate the spatial window; without an explicit, pre-mainshock definition of the area boundaries (independent of the 17 November epicenter), the reported approach to criticality on 15 November cannot be evaluated for post-hoc selection bias.

    Authors: We agree that the abstract (and the corresponding section of the main text) does not explicitly state the a-priori criteria used to define the candidate area. The area is chosen on the basis of the SES station location and the source-region estimates that follow from the recorded SES activity, using the same geophysical criteria employed in our earlier publications; these criteria pre-date the 17 November mainshock and do not incorporate its epicenter. Nevertheless, the absence of an explicit statement leaves the procedure open to the interpretation raised by the referee. In the revised manuscript we will add a concise description of the area-selection rules, together with the relevant references, so that the spatial window is fully specified before the mainshock occurrence. revision: yes

  2. Referee: [Abstract] Abstract and Note: the identification of the critical point on 15 November 2014 is presented as the outcome of the natural-time procedure, yet no quantitative values are given for the natural-time parameters (e.g., the exact threshold for the variance of natural time or the entropy measure) or for the number of events analyzed in the candidate area, preventing independent verification of the reported date.

    Authors: The manuscript reviews the natural-time procedure but does not tabulate the numerical values of κ₁, S, or the event count N that were obtained for the specific time series ending on 15 November 2014. These quantities are required for independent verification. In the revised version we will supply the relevant numerical results (including the precise values of the natural-time parameters at the moment criticality was declared and the number of events used) either in the main text or in a supplementary table, so that the date can be reproduced from the published seismicity catalogue. revision: yes

Circularity Check

1 steps flagged

Identification of critical point reduces to application of authors' prior natural time procedure after SES recording

specific steps
  1. self citation load bearing [Abstract]
    "The procedure by means of which the occurrence time of an impending mainshock can be identified by analyzing in natural time the seismicity in the candidate area subsequent to the recording of a precursory Seismic Electric Signals (SES) activity is reviewed. Here, we report the application of this procedure to an Mw5.4 mainshock that occurred in Greece on 17 November 2014 and was strongly felt in Athens. This mainshock ... was preceded by an SES activity recorded on 27 July 2014 and the results of the natural time analysis reveal that the system approached the critical point (mainshock) early"

    The claimed identification of the critical point is presented as the direct output of the reviewed procedure. Since the procedure itself originates from the authors' prior publications (as indicated by 'is reviewed' and the method's description), the reported 'result' is an instance of applying their own defined criteria and parameters rather than an independent derivation or prediction.

full rationale

The paper's central claim—that natural time analysis identifies the mainshock occurrence time on 15 Nov 2014—rests entirely on reviewing and applying the authors' established procedure for analyzing seismicity in a candidate area after SES activity. No independent external benchmark, pre-specified area selection criteria, or falsification test outside the method's own definitions is provided. This matches self-citation load-bearing where the result is forced by the authors' prior framework.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on the validity of SES as precursors and the natural time criticality criterion, both drawn from the authors' prior work without new independent evidence in this abstract.

axioms (2)
  • domain assumption SES activities are valid precursors to mainshocks
    Invoked in the abstract as the starting point for the analysis.
  • domain assumption Natural time analysis can identify the critical point from post-SES seismicity
    The procedure reviewed in the abstract assumes this identification is possible.

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Reference graph

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