A few minutes after the 8.8 magnitude earthquake that took place on 29 July in Kamchatka, Russia, the eruption of the Vulcano Klyuchevskoylocated about 450 km north from the city of Petropavlovsk-Kamcatsky. In addition, another eruption of the volcano also occurred on 4 August Krasheninnikovwhich shows new signs of activity after several centuries of quiescence. In the face of this phenomenon it is natural to ask if the earthquake and the eruptionespecially the first, they are connected. At the moment the correlation in the case of Kamchatka has not yet been confirmed, but past studies suggest that strong earthquakes are able to trigger volcanic eruptions in nearby areas, in the presence of certain conditions.
When earthquakes can cause volcanic eruptions
Based on the studies carried out so far, it seems that earthquakes can trigger volcanic eruptions in the presence of at least two conditions. First of all, the volcano must be ready to erupttherefore inside the magmatic chamber there must be a sufficient amount of magma and the pressure must be significant. Also an earthquake, to trigger an eruption, as well as being of high magnitude (higher than 6.0) must have a Hypocentro close enough At the volcano (the necessary distance, however, depends on the magnitude of the earthquake, so the more the earthquake is strong and the greater the distance of its hypocentro from the volcano may be). In addition to the magnitude, also duration, frequency and depth of the hypocenter of the earthquake play a decisive role.
In the presence of these conditions, strong earthquakes can do increase pressure in the magmatic chamber, determining the escape from the magma of the dissolved gases inside and consequently a volcanic eruption. Other manifestations that strong earthquakes can cause to volcanoes are, for example, the variation of the rates of deformation of the soil and the heat flow.
Based on the observations carried out over time, it seems that some volcanoes react to the earthquake quickly, in a few hours or daysdue to the solicitation induced by the passage of seismic waves through the volcanic system. In other cases, however, they can erupt even after months or even years.
The events that support the theory
Darwin He was the first to hypothesize that earthquakes could trigger volcanic eruptions. In the 1835in fact, during his expedition to Chile a strong earthquake took place, following which he noticed the increase in volcanic activity. Subsequently, there were other cases in which scientists hypothesized the correlation. For example, the magnitude 8.7 earthquake of 1707 in Japan It was followed 49 days after a violent explosive eruption of Mount Fuji. Also In Iceland, in 1618 and 1789 strong earthquakes They were followed by an increase in volcanic activity. A correlation between the 1975 earthquake in Hawaii, of magnitude 7.7and the eruption of the Kilauea two years later. A study, in particular, focused on Three strong earthquakes of magnitude greater than 7 that in 2012over two months, hit theCentral America. A few days later, some volcanic eruptions took place in the area, then continued in the following years. To confirm the theory, further data would be needed, which in the coming years will try to collect on the occasion of these events. It is also essential to continuously monitor the active volcanoes in order to understand which ones are most predisposed to erupt following a strong earthquake.
