Wikipedia

Seismo-electromagnetics

(Redirected from Seismo-electromagnetic)

Seismo-electromagnetics are various electro-magnetic phenomena believed to be generated by tectonic forces acting on the Earth's crust, and possibly associated with seismic activity such as earthquakes and volcanoes. Study of these has been prompted by the prospect they might be generated by the increased stress leading up to an earthquake, and might thereby provide a basis for short-term earthquake prediction. However, despite many studies, no form of seismo-electromagnetics has been shown to be effective for earthquake prediction. A key problem is that earthquakes themselves produce relatively weak electromagnetic phenomena, and the effects from any precursory phenomena are likely to be too weak to measure. Close monitoring of the Parkfield earthquake revealed no significant pre-seismic electromagnetic effects. However, some researchers remain optimistic, and searches for seismo-electromagnetic earthquake precursors continue.[citation needed]

VAN method

edit

The VAN method – named after P. Varotsos, K. Alexopoulos and K. Nomicos, authors of the 1981 papers describing it[1][2] – measures low frequency electric signals, termed "seismic electric signals" (SES), by which Varotsos and several colleagues claimed to have successfully predicted earthquakes in Greece.[3][4] Both the method itself and the manner by which successful predictions were claimed have been severely criticized[5][6][7] and debated by VAN, but the critics have not retracted their views.[8][9]

Since 2001, the VAN group has introduced a concept they call "natural time", applied to the analysis of their precursors. Initially it is applied on SES to distinguish them from noise and relate them to a possible impending earthquake. In case of verification (classification as "SES activity"), natural time analysis is additionally applied to the general subsequent seismicity of the area associated with the SES activity, in order to improve the time parameter of the prediction. The method treats earthquake onset as a critical phenomenon.[10][11][12][13]

After 2006, VAN say that all alarms related to SES activity have been made public by posting at arxiv.org. One such report was posted on Feb. 1, 2008, two weeks before the largest earthquake in Greece during the period 1983–2011. This earthquake occurred on February 14, 2008, with magnitude (Mw) 6.9. VAN's report was also described in an article in the newspaper Ethnos on Feb. 10, 2008.[14][15][16][17] However, Gerassimos Papadopolous complained that the VAN reports were confusing and ambiguous, and that "none of the claims for successful VAN predictions is justified",[18] but this complaint was answered on the same issue.[19]

QuakeFinder and 'Freund physics'

edit

In his investigations of crystalline physics, Friedemann Freund found that water molecules embedded in rock can dissociate into ions if the rock is under intense stress. The resulting charge carriers can generate battery currents under certain conditions. Freund suggested that perhaps these currents could be responsible for earthquake precursors such as electromagnetic radiation, earthquake lights and disturbances of the plasma in the ionosphere.[20] The study of such currents and interactions is known as "Freund physics".[21]

Most seismologists reject Freund's suggestion that stress-generated signals can be detected and put to use as precursors, for a number of reasons. First, it is believed that stress does not accumulate rapidly before a major earthquake, and thus there is no reason to expect large currents to be rapidly generated. Secondly, seismologists have extensively searched for statistically reliable electrical precursors, using sophisticated instrumentation, and have not identified any such precursors. And thirdly, water in the earth's crust would cause any generated currents to be absorbed before reaching the surface.[22]

QuakeFinder is a company focused on developing a system for earthquake prediction. The company has a long-standing collaboration with Freund.[23] They have deployed a network of sensor stations that detect the electromagnetic pulses the team believes precede major earthquakes.[24] Each sensor is believed to have a range of approximately 10 miles (16 km) from the instrument to the source of the pulses.[25] As of 2016, the company says they have 125 stations in California,[26] and their affiliate Jorge Heraud says he has 10 sites in Peru.[27] Using these sensors, Heraud says that he has been able to triangulate pulses seen from multiple sites, in order to determine the origin of the pulses. He said that the pulses are seen beginning from 11 to 18 days before an impending earthquake, and have been used to determine the location and timing of future seismic events.[28][29]

However, insofar as a verifiable prediction would require a publicly stated announcement of the location, time, and size of an impending event before its occurrence, neither Quakefinder nor Heraud have yet verifiably predicted an earthquake, much less issued multiple predictions of the type that might be objectively testable for statistical significance.

Current research suggests it's dissolved gases that come out of solution when de-pressurized and then ionize to generate the electrical signatures.[30]

Corralitos anomaly

edit

In the month prior to the 1989 Loma Prieta earthquake measurements of the Earth's magnetic field at ultra-low frequencies by a magnetometer in Corralitos, California, just 7 km from the epicenter of the impending earthquake, started showing anomalous increases in amplitude. Just three hours before the quake the measurements soared to about thirty times greater than normal, with amplitudes tapering off after the quake. Such amplitudes had not been seen in two years of operation, nor in a similar instrument located 54 km away. To many people such apparent locality in time and space suggested an association with the earthquake.[31]

Additional magnetometers were subsequently deployed across northern and southern California, but after ten years, and several large earthquakes, similar signals have not been observed. More recent studies have cast doubt on the connection, attributing the Corralitos signals to either unrelated magnetic disturbance[32] or, even more simply, to sensor-system malfunction.[33]

Study of the closely monitored 2004 Parkfield earthquake found no evidence of precursory electromagnetic signals of any type.[34]

ULF magnetic field precursors

edit

Two recent studies by Konstantinos Eftaxias and his colleagues examined ULF magnetic fields preceding major earthquakes. At the 2011 Tohoku earthquake, ULF radiation exhibited critical behavior,[35] while at the 2008 Sichuan earthquake, the researchers found a depression of the horizontal ULF magnetic field, which may also be interpreted as a manifestation of criticality.[36][37][better source needed]

TEC variations

edit

Professor Kosuke Heki of Hokkaido University in Japan said that he discovered by accident that GPS signals changed about 40 minutes before the 2011 Tohoku-Oki earthquake. Reviewing historical data for other earthquakes, he found that this same correlation occurred during other incidents. He suggested that the GPS signals were detecting variations in the levels of the TEC (total electron content) of the ionosphere in the hour preceding an earthquake.[38][39]

Satellite observations

edit

The "Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions" satellite, constructed by CNES, has made observations which show strong correlations between certain types of low frequency electromagnetic activity and the most seismically active zones on the Earth, and have shown a sharp signal in the ionospheric electron density and temperature near southern Japan seven days before a 7.1 magnitude earthquake occurred there (on August 29 and September 5, 2004, respectively).[40]

Quakesat is an earth observation nanosatellite based on 3 CubeSats. It was designed to be a proof-of-concept for collecting extremely low frequency earthquake precursor signals from space. The primary instrument is a magnetometer housed in a 2-foot (0.6 m) telescoping boom. The science behind the concept is disputed.[24]

ESPERIA is an equatorial space mission mainly concerned with detecting any tectonic and preseismic related signals. More in general, it has been proposed for defining the near-Earth electromagnetic, plasma, and particle environment, and for studying perturbations and instabilities in the ionosphere-magnetosphere transition region. To study earthquake preparation processes and anthropogenic impacts in the Earth's surface, a phase A study has been realized for the Italian Space Agency.[41]

The Deformation, Ecosystem Structure and Dynamics of Ice (DESDynI) radar satellite, which was canceled in the White House's 2012 budget proposal, would have the capacity to identify elastic strain in tectonic plates, combining L-band interferometric synthetic aperture radar and a multi-beam infrared lidar to detect strains in the Earth's surface that could lead to serious earthquakes.[42][43]

Russia and the United Kingdom agreed to jointly deploy two satellites in 2015 that will measure electromagnetic signals that are released from the earth's crust prior to earthquakes. The project is said to be able to "help predict earthquakes and potentially save thousands of lives."[44]

Another site of current research is China, where a satellite launch was planned for 2014, to provide data from ionospheric phenomena for comparison with seismo-electromagnetic phenomena on the ground. Such a link is partially borne out in the current literature, with ionospheric phenomena already shown to precede seismic phenomena by a few hours to days. The network would potentially show whether such ionospheric phenomena are sourced from ground electrical phenomena.[45]

See also

edit

References

edit
  1. ^ Varotsos, Alexopoulos & Nomicos 1981a, 1981b
  2. ^ Varotsos & Alexopoulos 1984
  3. ^ Varotsos & Kuhlanek 1993 (preface to a special edition about VAN)
  4. ^ Varotsos, Alexopoulos & Lazaridou 1993
  5. ^ Mulargia & Gasperini 1992
  6. ^ Geller 1997, §4.5
  7. ^ ICEF 2011, p. 335
  8. ^ Lighthill 1996 (proceedings of a conference that reviewed VAN)
  9. ^ twenty articles in a special issue of Geophysical Research Letters (table of contents)
  10. ^ Varotsos, Sarlis & Skordas 2002; Varotsos 2006.
  11. ^ Rundle et al. 2012.
  12. ^ Huang 2015.
  13. ^ Uyeda, Kamogawa & Tanaka 2009
  14. ^ Uyeda & Kamogawa 2008
  15. ^ Uyeda 2010
  16. ^ Apostolidis 2008.
  17. ^ Chouliaras 2009
  18. ^ Papadopoulos 2010
  19. ^ Uyeda & Kamogawa 2010
  20. ^ Freund 2000
  21. ^ Hough 2010, pp. 133–135
  22. ^ Hough 2010, pp. 137–139
  23. ^ "QuakeFinder's partnership with the SETI Institute". QuakeFinder. QuakeFinder. Retrieved March 12, 2017.
  24. ^ a b Upton, John (August 13, 2011). "Pursuing the Grail of an Earthquake Predictor, but Facing Skeptics". The New York Times. Retrieved 2011-08-28.
  25. ^ Sibley, Lisa (March 25, 2011). "QuakeFinder's mission: Detect quakes before they shake". Silicon Valley / San Jose Business Journal. American Cities Business Journals. Retrieved 2011-09-30.
  26. ^ "Quakefinder Blog". QuakeFinder. 2016. Retrieved 19 November 2016.
  27. ^ Heraud, Jorge (2016). "presenter bio". Singularity University Summit. Retrieved 19 November 2016.
  28. ^ Heraud, Centa & Bleier 2015
  29. ^ Enriquez 2015
  30. ^ Nield, David (30 May 2021). "Weird Electromagnetic Bursts Appear Before Earthquakes – And We May Finally Know Why". ScienceAlert. Retrieved 31 May 2021.
  31. ^ Fraser-Smith et al. (1990, p. 1467) called it "encouraging".
  32. ^ Campbell 2009
  33. ^ Thomas, Love & Johnston 2009
  34. ^ Park, Dalrymple & Larsen 2007, paragraphs 1 and 32. See also Johnston et al. 2006, p. S218 (no VAN-type SES observed) and Kappler, Morrison & Egbert 2010 ("no effects found that can be reasonably characterized as precursors").
  35. ^ Contoyiannis, Y.; Potirakis, S. M.; Eftaxias, K.; Hayakawa, M.; Schekotov, A. (2016-06-15). "Intermittent criticality revealed in ULF magnetic fields prior to the 11 March 2011 Tohoku earthquake ()". Physica A: Statistical Mechanics and its Applications. 452: 19–28. Bibcode:2016PhyA..452...19C. doi:10.1016/j.physa.2016.01.065.
  36. ^ Contoyiannis, Y.; Potirakis, S. M.; Eftaxias, K.; Hayakawa, M.; Schekotov, A. (2016-06-15). "Intermittent criticality revealed in ULF magnetic fields prior to the 11 March 2011 Tohoku earthquake ()". Physica A: Statistical Mechanics and its Applications. 452: 19–28. Bibcode:2016PhyA..452...19C. doi:10.1016/j.physa.2016.01.065.
  37. ^ For supporting information and review, see also Maggipinto, Tommaso; Biagi, Pier Francesco; Colella, Roberto; Schiavulli, Luigi; Ligonzo, Teresa; Ermini, Anita; Martinelli, Giovanni; Moldovan, Iren; Silva, Hugo (2015-01-01). "The LF radio anomaly observed before the Mw = 6.5 earthquake in Crete on October 12, 2013" (PDF). Physics and Chemistry of the Earth, Parts A/B/C. Earthquakes Precursors and Earthquake Prediction: Recent Advances. 85–86: 98–105. Bibcode:2015PCE....85...98M. doi:10.1016/j.pce.2015.10.010. hdl:2108/188111. and Fujinawa, Y.; Noda, Y.; Takahashi, K.; Kobayashi, M.; Takamatsu, K.; Natsumeda, J. (2013-12-31). "Field Detection of Microcracks to Define the Nucleation Stage of Earthquake Occurrence". International Journal of Geophysics. 2013: 1–18. doi:10.1155/2013/651823. ISSN 1687-885X.
  38. ^ Kosuke Heki, Ionospheric electron enhancement preceding the 2011 Tohoku-Oki earthquake, Geophysical Research Letters, V. 38, L17312, 5 PP., 2011 doi:10.1029/2011GL047908 abstract
  39. ^ BBC News
  40. ^ "Satellite défilant du CNES (France)". Archived from the original on 2006-07-16. Retrieved 2006-10-22. (in French)
  41. ^ Sgrignal, Vittorio; Console, Rodolfo; Conti, Livio; Moiseev Galper, Arkady; Malvezzil, Valeria; Parrot, Michel; Picozza, Piergiorgio; Scrimaglio, Renato; Spillantini, Piero; Zilpimiani, David. "The ESPERIA Project: a Mission to Investigate the near-Earth Space". Earth Observation with CHAMP: 407–412. doi:10.1007/3-540-26800-6_65.
  42. ^ Simons, Mark, "Budget Cuts and the Next Earthquake", Wall Street Journal, March 23, 2011
  43. ^ Morring Jr., Frank, "Funding Uncertainty Shaping NASA Programs", Aviation Week, Mar 28, 2011
  44. ^ "Russian, British scientists eye satellites to predict earthquakes", AHN, February 22, 2011
  45. ^ Shen, Xuhui, Xuemin Zhang, Lanwei Wang, Huaran Chen, Yun Wu, Shigeng Yuan, Junfeng Shen, Shufan Zhao, Jiadong Qian and Jianhai Ding (2011). "The earthquake-related disturbances in ionosphere and project of the first China seismo-electromagnetic satellite". Earthquake Science. 24 (6). Springer Science+Business Media: 639–650. Bibcode:2011EaSci..24..639S. doi:10.1007/s11589-011-0824-0.{{cite journal}}: CS1 maint: multiple names: authors list (link)

Sources

edit

Further reading

edit
Retrieved from "https://en.wikipedia.org/w/index.php?title=Seismo-electromagnetics&oldid=1256646622"