Some comments on the potential seismogenic origin of magnetic disturbances observed by Di Lorenzo et al. (2011) close to the time of the 6 April 2009 L'Aquila earthquake

Masci, F.; Luca, Giovanni De

doi:10.5194/nhess-13-1313-2013

Cited by 6 publications

(5 citation statements)

References 40 publications

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“…Thus, some researchers do not agree that magnetic changes observed prior to earthquakes had seismogenic origin. They have demonstrated that many published preearthquake ULF magnetic changes [see Campbell , ; Masci , , , , , , , ; Masci and De Luca , ; Masci and Thomas , , , ; Moldovan et al ., ; Romanova et al ., ; Thomas et al ., , ] and ionospheric disturbances [see Foppiano et al ., ; Masci , , ; Masci and Thomas , , ; Masci et al ., ; Thomas et al ., , ] are reasonably related to instrumentation malfunction, to the analysis procedure, or to the normal geomagnetic activity in response to Sun‐Earth interactions.…”

Section: Introductionmentioning

confidence: 99%

Are there new findings in the search for ULF magnetic precursors to earthquakes?

Masci

Thomas

2015

JGR Space Physics

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Moore (1964) in a letter published in Nature reported disturbances in geomagnetic field data prior to the 27 March 1964 Alaska earthquake. After the publication of this report, many papers have shown magnetic changes preceding earthquakes. However, a causal relationship between preearthquake magnetic changes and impending earthquakes has never been demonstrated. As a consequence, after 50 years, magnetic disturbances in the geomagnetic field are still candidate precursory phenomena. Some researchers consider the investigation of ultra low frequency (ULF: 0.001–10 Hz) magnetic data the correct approach for identifying precursory signatures of earthquakes. Other researchers, instead, have recently reviewed many published ULF magnetic changes that preceded earthquakes and have shown that these are not actual precursors. The recent studies by Currie and Waters (2014) and Han et al. (2014) aim to provide relevant new findings in the search for ULF magnetic precursory signals. However, in order to contribute to science, alleged precursors must be shown to be valid and reproducible by objective testing. Here we will briefly discuss the state of the art in the search for ULF magnetic precursors, paying special attention to the recent findings of Currie and Waters (2014) and Han et al. (2014). We do not see in these two reports significant evidence that may support the observation of precursory signatures of earthquakes in ULF magnetic records.

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Section: Introductionmentioning

confidence: 99%

Are there new findings in the search for ULF magnetic precursors to earthquakes?

Masci

Thomas

2015

JGR Space Physics

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“…Because the Earth's crust is fluid saturated, Dahlgren et al (2014) conclude that significant electric currents are not expected to be generated the days before earthquakes during the slow stress accumulation in the region of earthquake nucleation; as a consequence no electric and magnetic signals are expected to be observed on the Earth's surface. However, note that studies of data records from L'Aquila area (see Biagi et al, 2010;Masci, 2012b;Masci and Di Persio, 2012;Masci and De Luca, 2013;Villante et al, 2010) have identified no anomalous magnetic or electric effects during days to hours before and after the 6 April earthquake that might be hypothesized to have seismogenic origin. Still, in a recent report, Masci and Thomas (2016), by investigating magnetic field measurements from multiple magnetometers and seismic and strong motion records close to the earthquake epicentre, have shown that there is no evidence that might support the generation of an underground electric Nat.…”

Section: On the Hypothesized Generation Mechanismsmentioning

confidence: 95%

On a reported effect in ionospheric TEC around the time of the 6 April 2009 L'Aquila earthquake

Masci¹,

Thomas²,

Secan³

2017

Preprint

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Abstract. In a report published in Advances in Space Research, Nenovski et al. (2015) analyse ionospheric TEC data from GPS measurements around the time of 6 April 2009 Mw6.1 L'Aquila (Italy) earthquake. According to the authors, TEC difference (DTEC) calculated from two GPS receivers in central Italy shows a hump-like shape (an increase followed by a decrease) during the hours just before and shortly after the main shock. They maintain that the hump-like shape is anomalous and may be explained as related to the earthquake. We show that the DTEC increase the hours before the shock, as well as its subsequent slow decrease, do not have any characteristic that might support a possible relationship with the earthquake. We have also conducted our own independent analysis using the same GPS data analysed by Nenovski et al. (2015). We have found a daily modulation in DTEC time series that shows hump-like shapes like that reported by Nenovski et al. (2015) throughout the investigated period. This demonstrates that the hump-like shape in DTEC close to the time of the 6 April earthquake is not anomalous and cannot be considered a possible earthquake-related effect.

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“…No actual coseismic electric and magnetic effects in correspondence to the 6 April main shock have been yet identified, and reported magnetic changes claimed to be related to this earthquake have been shown not to be seismogenic Masci and De Luca, 2013].…”

Section: The 6 April 2009 L'aquila Earthquakementioning

confidence: 95%

“…Studies using data from L'Aquila area, instead, did not identify magnetic changes that can be actually put in relation with the 6 April earthquake [see, e.g., Masci and Di Persio , ; Villante et al , ]. No actual coseismic electric and magnetic effects in correspondence to the 6 April main shock have been yet identified, and reported magnetic changes claimed to be related to this earthquake have been shown not to be seismogenic [ Masci , ; Masci and De Luca , ].…”

Section: The 6 April 2009 L'aquila Earthquakementioning

confidence: 99%

“…As should be done in reports of alleged precursors of earthquakes, also, papers showing coseismic electric and magnetic changes should provide an adequate control of the origin of the reported effects. The correspondence between the identified electric and magnetic effects and the shock may be just a coincidence, may result from careless data analysis, or may be an instrumental effect [see, e.g., Masci and De Luca , ]. Independent measurements may provide convincing evidence that an observed coseismic disturbance is or is not related to an actual seismoelectric effect.…”

Section: Introductionmentioning

confidence: 99%

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Evidence of underground electric current generation during the 2009 L'Aquila earthquake: Real or instrumental?

Masci

Thomas

2016

Geophysical Research Letters

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We investigate magnetic effects in correspondence of the Mw6.1 L'Aquila earthquake. Magnetic and seismic records are analyzed. Rapid and distinct changes and an offset can be seen in magnetic field components after the main shock. We show that these effects result from electromagnetic induction due to the movement of the sensors through the Earth's magnetic field and from a permanent displacement of the sensors from their original position caused by the passing seismic waves. A transient signal in total field data from an overhauser magnetometer apparently occurs in correspondence with the earthquake. Our analysis shows that the transient was not observed by other sensors that were operating in close proximity to the overhauser. Thus, the transient signal in the total magnetic field data, and the offset in the magnetic field components, cannot be associated with a hypothetical underground electric current generated by the earthquake, as suggested by Nenovski (2015).

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Some comments on the potential seismogenic origin of magnetic disturbances observed by Di Lorenzo et al. (2011) close to the time of the 6 April 2009 L'Aquila earthquake

Cited by 6 publications

References 40 publications

Are there new findings in the search for ULF magnetic precursors to earthquakes?

Are there new findings in the search for ULF magnetic precursors to earthquakes?

On a reported effect in ionospheric TEC around the time of the 6 April 2009 L'Aquila earthquake

Evidence of underground electric current generation during the 2009 L'Aquila earthquake: Real or instrumental?

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