Scientists have identified a pattern in a series of six major earthquakes that occurred in the Iranian region between 2014 and 2021. These earthquakes ranged in magnitude from 6.0 to 7.3. The analysis revealed that several months prior to the earthquakes, an increase in pressure within the Earth's crust was observed, accompanied by intensified magnetic fluctuations above the Earth's surface.
Data from the European Space Agency (ESA) Swarm satellite mission were used for this study. Specialists examined magnetic changes within a radius of about 300 kilometers from the earthquake epicenters, comparing them with seismic activity in the area. Nevertheless, the authors emphasize that this does not imply the possibility of accurately predicting the date or location of an earthquake using satellites.
The following cases were examined as part of the study of six significant seismic events: the Murumuri earthquake with a magnitude of 6.2, which occurred on August 18, 2014; the Khojedak earthquake with a magnitude of 6.2, which happened on December 1, 2017; the Azgelekh earthquake with a magnitude of 7.3, dated November 12, 2017; the Fin earthquake with a magnitude of 6.4 in 2021; and the Sefidsang earthquake with a magnitude of 6.0, which occurred near Afghanistan.
The scientists also paid attention to the b-value, which allows for the assessment of the ratio of small to large earthquakes in a specific area. A decrease in the b-value may indicate an increase in pressure in the rock formations. In many cases, a decrease in the b-value coincided with an increase in magnetic fluctuations registered by satellites.
Approximately 105–20 days before the Murumuri earthquake, a drop in the b-value was recorded, during which three satellites registered magnetic changes. According to one dataset, five magnetic changes were noted one day before the earthquake, approximately 64 days prior to the event.
In the case of the Khojedak earthquake, these changes were more evident: the b-value dropped sharply approximately 100–200 days before the earthquake, accompanied by increased magnetic activity. This means that in this case, the changes began to manifest 3–6 months before the earthquake.
When pressure on rock formations increases, small cracks can form. These cracks are capable of altering the electromagnetic properties of the rocks and also facilitating the release of gases and other substances. Scientists hypothesize that these changes may propagate into the upper atmosphere and the ionosphere.
However, it should be noted that not all magnetic fluctuations in the ionosphere are caused by earthquakes; solar activity and geomagnetic storms can also cause similar changes. Therefore, researchers filtered out data related to periods of high solar and Earth's magnetic field activity.
According to the scientists, this study demonstrates only a potential correlation. Currently, it cannot be asserted that the date, location, or strength of an earthquake can be predicted using satellite data. Further analysis of data from a larger number of earthquakes from different countries and regions is necessary to confirm this hypothesis.
The main value of this study lies in the fact that a similar pattern was identified before the six major earthquakes between increasing underground pressure and magnetic fluctuations above ground. If this is confirmed in future research, satellite data may help in understanding the changes preceding earthquakes.
