Analysis of pre-earthquake ionospheric anomalies before the global &amp;lt;i&amp;gt;M&amp;lt;/i&amp;gt; = 7.0+ earthquakes in 2010

Self Cite

Observations from the South African TrigNet global navigation satellite system (GNSS) and vertical total electron content (VTEC) data from the Jason-1 satellite were used to analyze the variations in ionospheric electron density profiles over South Africa before and after the severe geomagnetic storms on 15 May 2005. Computerized ionospheric tomography (CIT) was used to inverse the 3-D structure of ionospheric electron density and its response to the magnetic storms. Inversion results showed that electron density significantly increased at 10:00 UT, 15 May compared with that at the same period on 14 May. Positive ionospheric storms were observed in the inversion region during the magnetic storms. Jason-1 data show that the VTEC observed on descending orbits on 15 May significantly increased, whereas that on ascending orbits only minimally changed. This finding is identical to the CIT result

Section: Published By Copernicus Publications On Behalf Of the Europesupporting

confidence: 53%

Temporal and spatial variations in ionospheric electron density profiles over South Africa during strong magnetic storms

Yao

Chen

Zhang

et al. 2013

Self Cite

“…After the work on the Christchurch precursor reports was complete, a paper appeared (Yao et al, 2012), which used data from the Global Navigation Satellite System (GPS) to pinpoint ionospheric precursors for the September event. The paper also reported similar geomagnetic precursors.…”

Section: Methodsmentioning

confidence: 99%

“…4. Lost pet data for Christchurch, with ionospheric data superimposed (Yao et al, 2012). The data from The Press are from pets lost at least one day prior.…”

Section: Lost/found Petsmentioning

confidence: 99%

See 1 more Smart Citation

Macroscopic anomalies before the September 2010 M = 7.1 earthquake in Christchurch, New Zealand

Whitehead¹,

Ulusoy

2013

Abstract. Previous published work after the Kobe andİzmit earthquakes (1995 and 1999, respectively) demonstrated some reported meteorological and animal behaviour precursors were valid. Predictions were freshly tested for the Christchurch earthquake (M = 7.1, 4 September 2010). An internet survey with nearly 400 valid replies showed relative numbers of reports in precursor categories the day before the quake, were statistically significantly different from those in the preceding three days (excess meteorological events and animal behaviour). The day before the quake, there was also altered relative precursor class occurrence within 56 km compared with further away. Both these confirmed the earlier published work. Owners were woken up by unique pet behaviour 12 times as often in the hour before the quake compared with other hours immediately before (statistically highly significant). Lost and Found pet reports were double normal the week before, and 4.5 times normal both the day before the quake, and 9 days before. (Results were again statistically significant). Unique animal behaviour before the quake was often repeated before the numerous aftershocks. These pet owners claimed an approximate 80 % prediction reliability. However, a preliminary telephone survey suggested that animals showing any precursor response are a minority. Some precursors seem real, but usefulness seemed mostly restricted to 7 cases where owners were in, or near, a place of safety through disruptive pet behaviour, and one in which owners were diverted by a pet from being struck by falling fixtures. For a later 22 February 2011 M = 6.3 quake no reports of escape through warning by pets were recorded, which raises serious questions whether such prediction is practically useful, because lives claimed saved are extremely low compared with fatalities. It is shown the lost-pet statistics dates, correspond to ionospheric anomalies recorded using the GPS satellite system and geomagnetic disturbance data, and claimed as precursory. The latter more objective measurements may be the way of the future, but improved statistical treatment should include observations over longer periods of time without earthquakes.

“…In the application, for which Bernese v5.0 academic software was used, approximate coordinates were calculated with PPP (Yildirim et al, 2013). The approximate coordinates were calculated by using the satellite-receiver time er- rors generated in 5 min intervals by IGS, in addition to the code and phase measurements of the CORS-TR stations.…”

Section: Determining the Seismic Origin Positional Variationmentioning

confidence: 99%

Review of variations in Mw < 7 earthquake motions on position and TEC (Mw = 6.5 Aegean Sea earthquake sample)

Yıldırım

İnyurt

Mekik

2016

Abstract. Turkey is a country located in the middle latitude zone, where tectonic activity is intensive. Recently, an earthquake of magnitude 6.5  Mw occurred offshore in the Aegean Sea on 24 May 2014 at 09:25 UTC, which lasted about 40 s. The earthquake was also felt in Greece, Romania, and Bulgaria in addition to Turkey. In recent years, ionospheric anomaly detection studies have been carried out because of seismicity with total electron content (TEC) computed from the global navigation satellite system's (GNSS) signal delays and several interesting findings have been published. In this study, both TEC and positional variations have been examined separately following a moderate size earthquake in the Aegean Sea. The correlation of the aforementioned ionospheric variation with the positional variation has also been investigated. For this purpose, a total of 15 stations was used, including four continuously operating reference stations in Turkey (CORS-TR) and stations in the seismic zone (AYVL, CANA, IPSA, and YENC), as well as international GNSS service (IGS) and European reference frame permanent network (EPN) stations. The ionospheric and positional variations of the AYVL, CANA, IPSA, and YENC stations were examined using Bernese v5.0 software. When the precise point positioning TEC (PPP-TEC) values were examined, it was observed that the TEC values were approximately 4 TECU (total electron content unit) above the upper-limit TEC value at four stations located in Turkey, 3 days before the earthquake at 08:00 and 10:00 UTC. At the same stations, on the day before the earthquake at 06:00, 08:00, and 10:00 UTC, the TEC values were approximately 5 TECU below the lower-limit TEC value. The global ionosphere model TEC (GIM-TEC) values published by the Centre for Orbit Determination in Europe (CODE) were also examined. Three days before the earthquake, at all stations, it was observed that the TEC values in the time period between 08:00 and 10:00 UTC were approximately 2 TECU above the upper-limit TEC value; 1 day before the earthquake at 06:00, 08:00, and 10:00 UTC, the TEC values were approximately 4 TECU below the lower-limit TEC value. Again, by using the same 15 stations, positional variation investigation for before and after the earthquake was undertaken for the AYVL, CANA, IPSA, and YENC stations. As a result of the conducted analysis, positional displacements were seen before and after the earthquake at the CANA station, which is the nearest station to the earthquake centre. Before and after the earthquake, positional displacements were observed as 10 and 3 cm respectively.