Part.1 How does heavy rain cause a volcanic eruption? Located in the southeastern part of the Island of Hawaii, Kilauea is not only one of the largest and most spectacular craters in the world, but also one of the world’s youngest active volcanoes. Its most recent massive eruption, which caused hundreds of houses to collapse and forced the evacuation of more than 1,700 residents, between May and August 2018.
The researchers looked at the eruption of The Kilauea volcano in 2018 to try to find out why the eruption was.
In general, before a volcano erupts, magma inside the volcano continues to gather and exert pressure on the rocks on the surface, and when the pressure is high enough, the magma breaks through the rock formation to reach the surface, eventually leading to volcanic eruptions.
Similar pressures can cause the ground to form tens of centimeters of bulge, which is a possible sign of volcanic eruptions. But to the researchers’ doubts, there was no apparent ground uplift before the eruption of the Kilauea volcano, and traditional theories do not provide a good explanation for the large-scale eruption.
If it is not an internal role, will it be the role of external forces?
With this question in mind, the researchers turned their attention to precipitation. The result was a startling discovery, with unusually heavy precipitation in Hawaii in the first few months of the eruption! During this period, the total rainfall in the area was as high as 2.25 metres, with 1.26 metres falling from 14 to 15 April alone. The multi-year average of precipitation over the same period in the region over the past 19 years is only 0.9 meters.
Dream to find him a thousand baidu, suddenly look back, is this abnormal volcanic eruption is caused by heavy rainfall?
The results of the follow-up were even more encouraging for researchers, who found that rain from heavy rainfall in the early stages of the eruption was seeping down the fissures and pores of volcanic rock, reaching a maximum of 2.9 kilometers underground, causing pore pressure inside the Kilauea volcano to rise to its highest level in nearly 50 years on the eve of and during the eruption, weakening and destroying the rock formations and allowing magma to enter the veast.
In other words, it is not the pressure of the underground magma that increases, but the pressure caused by the rain, which makes the cracks between the rocks more fragile, eventually triggering the eruption.
Unusual precipitation anomalies in the early stages of the 2018 Kilauea volcano eruption
Can this be explained by the case of the Kilauea eruption?
No, it didn’t. These are just one inference, and more evidence is needed to turn this inference into a conclusion.
So the researchers modeled the eruption, simulating the accumulation of rainwater seeping down deep rock crevices. The results show that rainwater may seep into the rock pores to increase the pressure. The increasing water content of the rock formations weakens the structure of the volcano, making magma easier to enter the rock pores, which eventually leads to volcanic eruptions.
Finally, the researchers analyzed the historical eruptions of The Kiravea volcano, and the results were even more surprising. Since 1790, 60% of the eruptions of The Kilauea volcano have been experienced by the rainy season of about six months.
After excluding the pull factors including the sun, the moon’s gravity and the pressure of the new magma below, they further found that volcanoes were twice as likely to erupt during the rainy season as at other times. This suggests a link between rainfall and the historical eruptions of Kilauea.
On April 22nd the British journal Nature published the findings by Jamie Farquharson’s team at the University of Miami.
Of course, is there a similar relationship between other volcanoes and precipitation, which this study only targets kilauea volcanoes? After all, there seems to be some chance to take a single study case.
Several studies suggest that this is no coincidence.
Heavy rainfall caused by the 1989-1991 storm may have played an important role in the eruption of Mount St. Helens. During 2001, Mount Soufriere, in Montserrat, had heavy rainfall before and during the eruption. In addition, the rains may have triggered the eruption of the Mount Vernes on the French island of Reunion in late 2008.
Is it as long as the rain will exacerbate the volcanic eruption?
Is it as long as the rain will exacerbate the volcanic eruption? The answer, of course, is no. Only unusually heavy rainfall is likely to trigger volcanic eruptions. However, if heavy rainfall events continue to increase, many of the volcanoes that would have quietly been watched by humans may become less comfortable. The bad news is that the probability of heavy rainfall on Earth is increasing against a backdrop of rapid global warming.
In the past, the amount of heavy rainfall in the world has increased significantly
As global warming continues, the total, frequency and intensity of heavy rainfall on land have increased globally since 1950, with significantly more areas than areas with significant decreases in the number of extreme heavy precipitation events, according to a study by the United Nations Intergovernmental Panel on Climate Change (IPCC).
In addition, climate models were used to analyze the frequency of extreme precipitation events in different temperature-rising scenarios (1.5 degrees C and 2 degrees C) in the global monsoon region in the future. It was found that an increase of 0.5 degrees C in warming would greatly increase the probability of extreme precipitation events in the global monsoon region. This means that many volcanoes around the world are likely to experience similar conditions in Kilauea, and many otherwise quiet volcanoes will become increasingly uneasy as heavy precipitation increases.