View source for Physics:Seismo-electromagnetics

{{Short description|Electro-magnetic phenomena}}

'''Seismo-electromagnetics''' are various [[Physics:Electromagnetic radiation|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|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|date=March 2017}}

==VAN method==

The [[Earth:VAN method|VAN method]] – named after P. Varotsos, K. Alexopoulos and K. Nomicos, authors of the 1981 papers describing it<ref>{{Harvs|nb|last1=Varotsos |last2=Alexopoulos |last3=Nomicos |year=1981a|year2=1981b}}</ref><ref name="Varotsos 1984">{{Harvnb|Varotsos|Alexopoulos|1984}}</ref> – measures low frequency electric signals, termed "seismic electric signals" (SES), by which Varotsos and several colleagues claimed to have successfully [[Earthquake prediction|predicted earthquakes]] in Greece.<ref>{{Harvnb|Varotsos|Kuhlanek|1993}} (preface to a special edition about VAN)</ref><ref name="Varotsos 1993">{{Harvnb|Varotsos|Alexopoulos|Lazaridou|1993}}</ref> Both the method itself and the manner by which successful predictions were claimed have been severely criticized<ref name="Mulargia 1992">{{Harvnb|Mulargia|Gasperini|1992}}</ref><ref name="Geller 1997 loc=§4.5">{{Harvnb|Geller|1997|loc=§4.5}}</ref><ref>{{Harvnb|ICEF|2011|p=335}}</ref> and debated by VAN, but the critics have not retracted their views.<ref>{{Harvnb|Lighthill|1996}} (proceedings of a conference that reviewed VAN)</ref><ref name="20_GRL">twenty articles in a special issue of [[Earth:Geophysical Research Letters|Geophysical Research Letters]] ([http://onlinelibrary.wiley.com/doi/10.1002/grl.v23.11/issuetoc table of contents])</ref>

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 (signal processing)|noise]] and relate them to a possible impending earthquake. In case of verification (classification as "SES activity"), [[Natural time analysis|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 phenomena|critical phenomenon]].<ref>{{Harvnb|Varotsos|Sarlis|Skordas|2002}}; {{Harvnb|Varotsos|2006}}.</ref><ref>{{Harvnb|Rundle et al.|2012}}.</ref><ref>{{Harvnb|Huang|2015}}.</ref><ref name="Uyeda 2009">{{Harvnb|Uyeda|Kamogawa|Tanaka|2009}}</ref>

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 ({{M|w|link=y}}) 6.9. VAN's report was also described in an article in the newspaper Ethnos on Feb. 10, 2008.<ref>{{Harvnb|Uyeda|Kamogawa|2008}}</ref><ref>{{Harvnb|Uyeda|2010}}</ref><ref>{{Harvnb|Apostolidis|2008}}.</ref><ref>{{Harvnb|Chouliaras|2009}}</ref> However, Gerassimos Papadopolous complained that the VAN reports were confusing and ambiguous, and that "none of the claims for successful VAN predictions is justified",<ref>{{Harvnb|Papadopoulos|2010}}</ref> but this complaint was answered on the same issue.<ref>{{Harvnb|Uyeda|Kamogawa|2010}}</ref>

==QuakeFinder and 'Freund physics'==

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.<ref>{{Harvnb|Freund|2000}}</ref> The study of such currents and interactions is known as "Freund physics".<ref>{{Harvnb|Hough|2010|pages=133–135}}</ref>

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.<ref>{{Harvnb|Hough|2010|pages=137–139}}</ref>

[[Earth:QuakeFinder|QuakeFinder]] is a company focused on developing  a system for [[Earthquake prediction|earthquake prediction]]. The company has a long-standing collaboration with Freund.<ref>{{cite web|title=QuakeFinder's partnership with the SETI Institute|url=https://www.quakefinder.com/quakefinders-partnership-with-the-seti-institute/|website=QuakeFinder|publisher=QuakeFinder|access-date=March 12, 2017}}</ref> They have deployed a network of sensor stations that detect the electromagnetic pulses the team believes precede major earthquakes.<ref name=nyt_upton/> Each sensor is believed to have a range of approximately 10 miles (16&nbsp;km) from the instrument to the source of the pulses.<ref>{{cite web | url = http://www.bizjournals.com/sanjose/print-edition/2011/03/25/quakefinder-mission-detect-quakes-before.html | title = QuakeFinder's mission: Detect quakes before they shake | date = March 25, 2011 | access-date = 2011-09-30 | first = Lisa | last = Sibley | work = Silicon Valley / San Jose Business Journal | publisher = American Cities Business Journals }}</ref> As of 2016, the company says they have 125 stations in California,<ref>{{cite web|title=Quakefinder Blog|url=https://www.quakefinder.com/thank-you-henry-dela-pena/|website=QuakeFinder|access-date=19 November 2016|date=2016}}</ref> and their affiliate Jorge Heraud says he has 10 sites in Peru.<ref>{{cite web|last1=Heraud|first1=Jorge|title=presenter bio|url=https://exponential.singularityu.org/summit/presenters/jorge-heraud/|website=Singularity University Summit|access-date=19 November 2016|date=2016}}</ref> 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.<ref>{{Harvnb|Heraud|Centa|Bleier|2015}}</ref><ref>{{Harvnb|Enriquez|2015}}</ref>

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.<ref>{{cite news |last1=Nield |first1=David |title=Weird Electromagnetic Bursts Appear Before Earthquakes – And We May Finally Know Why |url=https://www.sciencealert.com/weird-electromagnetic-bursts-appear-before-earthquakes-and-we-may-finally-know-why |access-date=31 May 2021 |work=ScienceAlert |date=30 May 2021}}</ref>

== Corralitos anomaly ==

In the month prior to the 1989 Loma Prieta earthquake measurements of the Earth's magnetic field at ultra-low frequencies by a [[Physics:Magnetometer|magnetometer]] in Corralitos, California, just 7&nbsp;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&nbsp;km away. To many people such apparent locality in time and space suggested an association with the earthquake.<ref>{{Harvtxt|Fraser-Smith|Bernardi|McGill|Ladd|1990| p=1467}} called it "encouraging".</ref>

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<ref>{{Harvnb|Campbell|2009}}</ref> or, even more simply, to sensor-system malfunction.<ref>{{Harvnb|Thomas|Love|Johnston|2009}}</ref>

Study of the closely monitored 2004 Parkfield earthquake found no evidence of precursory electromagnetic signals of any type.<ref>{{Harvnb|Park|Dalrymple|Larsen|2007|loc=paragraphs 1 and 32}}. See also {{Harvnb|Johnston|Sasai|Egbert|Mueller|2006|p=S218}} (no VAN-type SES observed) and {{Harvnb|Kappler|Morrison|Egbert|2010}} ("no effects found that can be reasonably characterized as precursors").</ref>

==ULF magnetic field precursors==

Two recent studies by Konstantinos Eftaxias and his colleagues examined [[Physics:Ultra low frequency|ULF]] magnetic fields preceding major earthquakes. At the  2011 Tohoku earthquake, ULF radiation exhibited critical behavior,<ref>{{Cite journal|last=Contoyiannis|first=Y.|last2=Potirakis|first2=S. M.|last3=Eftaxias|first3=K.|last4=Hayakawa|first4=M.|last5=Schekotov|first5=A.|date=2016-06-15|title=Intermittent criticality revealed in ULF magnetic fields prior to the 11 March 2011 Tohoku earthquake ()|journal=Physica A: Statistical Mechanics and its Applications|volume=452|pages=19–28|doi=10.1016/j.physa.2016.01.065|bibcode=2016PhyA..452...19C}}</ref> 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.<ref>{{Cite journal|last=Contoyiannis|first=Y.|last2=Potirakis|first2=S. M.|last3=Eftaxias|first3=K.|last4=Hayakawa|first4=M.|last5=Schekotov|first5=A.|date=2016-06-15|title=Intermittent criticality revealed in ULF magnetic fields prior to the 11 March 2011 Tohoku earthquake ()|journal=Physica A: Statistical Mechanics and its Applications|volume=452|pages=19–28|doi=10.1016/j.physa.2016.01.065|bibcode=2016PhyA..452...19C}}</ref><ref>For supporting information and review, see also {{Cite journal|last=Maggipinto|first=Tommaso|last2=Biagi|first2=Pier Francesco|last3=Colella|first3=Roberto|last4=Schiavulli|first4=Luigi|last5=Ligonzo|first5=Teresa|last6=Ermini|first6=Anita|last7=Martinelli|first7=Giovanni|last8=Moldovan|first8=Iren|last9=Silva|first9=Hugo|date=2015-01-01|title=The LF radio anomaly observed before the Mw&nbsp;=&nbsp;6.5 earthquake in Crete on October 12, 2013|url=https://art.torvergata.it/bitstream/2108/188111/1/JPCEproofs.pdf |journal=Physics and Chemistry of the Earth, Parts A/B/C|series=Earthquakes Precursors and Earthquake Prediction: Recent Advances|volume=85–86|pages=98–105|doi=10.1016/j.pce.2015.10.010|bibcode=2015PCE....85...98M|hdl=2108/188111|hdl-access=free}} and {{Cite journal|last=Fujinawa|first=Y.|last2=Noda|first2=Y.|last3=Takahashi|first3=K.|last4=Kobayashi|first4=M.|last5=Takamatsu|first5=K.|last6=Natsumeda|first6=J.|date=2013-12-31|title=Field Detection of Microcracks to Define the Nucleation Stage of Earthquake Occurrence|url=https://www.hindawi.com/journals/ijge/2013/651823/abs/|journal=International Journal of Geophysics|language=en|volume=2013|pages=1–18|doi=10.1155/2013/651823|issn=1687-885X|doi-access=free}}</ref>{{Better source needed|reason=Relatively brief mentions in secondary reviews|date=March 2017}}

==TEC variations==

Professor Kosuke Heki of Hokkaido University in {{wipe|Japan}} said that he discovered by accident that [[Engineering:GPS|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 [[Astronomy:Total electron content|TEC (total electron content)]] of the ionosphere in the hour preceding an earthquake.<ref>Kosuke Heki, ''Ionospheric electron enhancement preceding the 2011 Tohoku-Oki earthquake,'' Geophysical Research Letters, V. 38, L17312, 5 PP., 2011 
doi:10.1029/2011GL047908 [http://www.agu.org/pubs/crossref/2011/2011GL047908.shtml abstract]</ref><ref>[https://www.bbc.co.uk/news/science-environment-17487482/ BBC News]</ref>

==Satellite observations==

The "Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions" satellite, constructed by [[Organization:CNES|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 [[Astronomy:Ionosphere|ionospheric]] [[Physics:Electron|electron]] [[Physics:Density|density]] and [[Physics:Temperature|temperature]] near southern Japan seven days before a 7.1 magnitude earthquake occurred there (on August 29 and September 5, 2004, respectively).<ref>{{cite web
 | url=http://lettres-histoire.ac-rouen.fr/histgeo/demeter.htm
 | title=Satellite défilant du CNES (France)
 | access-date=2006-10-22
|archive-url = https://web.archive.org/web/20060716143101/http://lettres-histoire.ac-rouen.fr/histgeo/demeter.htm <!-- Bot retrieved archive --> |archive-date = 2006-07-16}} {{in lang|fr}}</ref>

Quakesat is an earth observation [[Engineering:Nanosatellite|nanosatellite]] based on 3 [[Engineering:CubeSat|CubeSat]]s. It was designed to be a proof-of-concept for collecting [[Physics:Extremely low frequency|extremely low frequency]] earthquake precursor signals from space. The primary instrument is a [[Physics:Magnetometer|magnetometer]] housed in a 2-foot (0.6 m) telescoping boom. The science behind the concept is disputed.<ref name=nyt_upton>{{cite news | title = Pursuing the Grail of an Earthquake Predictor, but Facing Skeptics | first = John | last = Upton | date = August 13, 2011 | newspaper = {{wipe|New York Times}} | url = https://www.nytimes.com/2011/08/14/us/14bcquakefinder.html | access-date = 2011-08-28 }}</ref>

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-[[Astronomy:Magnetosphere|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 [[Organization:Italian Space Agency|Italian Space Agency]].<ref>{{cite journal | doi=10.1007/3-540-26800-6_65 | title=The ESPERIA Project: a Mission to Investigate the near-Earth Space | journal=Earth Observation with CHAMP | pages=407–412 | last1 = Sgrignal | first1 = Vittorio | last2 = Console | first2 = Rodolfo | last3 = Conti | first3 = Livio | last4 = Moiseev Galper | first4 = Arkady | last5 = Malvezzil | first5 = Valeria | last6 = Parrot | first6 = Michel | last7 = Picozza | first7 = Piergiorgio | last8 = Scrimaglio | first8 = Renato | last9 = Spillantini | first9 = Piero | last10 = Zilpimiani | first10 = David}}</ref>

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 [[Engineering:Lidar|lidar]] to detect strains in the Earth's surface that could lead to serious earthquakes.<ref>Simons, Mark, [https://www.wsj.com/articles/SB10001424052748703858404576215052041762600?mod=googlenews_wsj "Budget Cuts and the Next Earthquake"], ''Wall Street Journal'', March 23, 2011</ref><ref>Morring Jr., Frank, [http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news/asd/2011/03/28/08.xml&headline=Funding%20Uncertainty%20Shaping%20NASA%20Programs "Funding Uncertainty Shaping NASA Programs"], ''Aviation Week'', Mar 28, 2011</ref>

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."<ref>[http://www.dbune.com/news/tech/4524-russian-british-scientists-eye-satellites-to-predict-earthquakes.html "Russian, British scientists eye satellites to predict earthquakes"], AHN, February 22, 2011</ref>

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.<ref>{{cite journal|author=Shen, Xuhui, Xuemin Zhang, Lanwei Wang, Huaran Chen, Yun Wu, Shigeng Yuan, Junfeng Shen, Shufan Zhao, Jiadong Qian and Jianhai Ding|year=2011|title=The earthquake-related disturbances in ionosphere and project of the first China seismo-electromagnetic satellite|journal=Earthquake Science|publisher=[[Company:Springer Science+Business Media|Springer Science+Business Media]]|volume=24|number=6|pages=639–650|doi=10.1007/s11589-011-0824-0|bibcode = 2011EaSci..24..639S |doi-access=free}}</ref>

==See also==
*[[Electrical resistivity tomography]]
*[[Earth:Induced polarization|Induced polarization]]
*[[Physics:Magnetometer|Magnetometer]]
*[[Earth:Seismoelectrical method|Seismoelectrical method]]
*[[Earth:Telluric current|Telluric current]]
*[[Earth:VAN method|VAN method]]

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{{refend}} {{div col end}}

==Further reading==
{{refbegin}}

*Seismo electromagnetics: [[Earth:Lithosphere|lithosphere]]-atmosphere-ionosphere coupling, Masashi Hayakawa, Oleg A. Molchanov, TerraPub, 2002, {{ISBN|978-4-88704-130-1}}
*[http://geomag.usgs.gov/downloads/publications/Thomas_et_al_Loma_Prieta_PEPI_2009.pdf On the reported magnetic precursor of the 1989 Loma Prieta earthquake], Jeremy N. Thomas, Jeffrey J. Love, Malcolm J.S. Johnston, Phys. Earth Planet. Int., 173, 207–215, doi:10.1016/j.pepi.2008.11.014, 2009.
*[https://books.google.com/books?id=aRORTGBbgX0C Ionospheric precursors of earthquakes], Sergey Pulinets, Kirill Boyarchuk, Springer, 2004, {{ISBN|978-3-540-20839-6}}
*Electromagnetic Phenomenon Related to Earthquakes and Volcanoes, Birbal Singh, Narosa Pub. House, 2008, 17 Jun 2009, {{ISBN|978-81-7319-858-8}}
*[https://books.google.com/books?id=JdGtYuxYX0cC A Critical review of VAN: earthquake prediction from seismic electrical signals], James Lighthill, World Scientific, 1996, {{ISBN|978-981-02-2542-1}}
*[https://web.archive.org/web/20110713003150/http://www.idsemergencymanagement.com/Common/Paper/Paper_251/Monitoring%20of%20ULF.pdf Monitoring of ULF (ultra-low-frequency) Geomagnetic Variations Associated with Earthquakes], Masashi Hayakawa, Katsumi Hattori and Kenji Ohta, Sensors 2007, 7, 1108–1122
*[https://web.archive.org/web/20111009162956/http://www.stat.ncu.edu.tw/teacher/yichen/Precursors%20paper/P8.pdf Pre-earthquake ionospheric anomalies registered by continuous GPS TEC measurements], J. Y. Liu, Y. J. Chuo, S. J. Shan, Y. B. Tsai, Y. I. Chen, S. A. Pulinets, and S. B. Yu, Annales Geophysicae (2004) 22: 1585–1593

[[Category:Geomagnetism]]
[[Category:Seismology]]

{{Sourceattribution|Seismo-electromagnetics}}