Some volcanic history and a new study

One of the topics I will often feature in this column is volcanic activity. Last week marked the 142nd anniversary of the massive eruption of Krakatoa. This explosion was one of the most powerful volcanic events in recorded history.

Krakatoa, which is known today as Krakatau, is a volcanic island in the Sunda Strait between Java and Indonesia in Indonesia. A series of four enormous explosions occurred Aug. 26-27, 1883. The eruption was the loudest volcanic explosion that has ever been heard. It was so intense that sailors on ships that were within approximately 40 miles went permanently deaf from the shockwaves of the huge eruption.

As the loudest sound in human history, the eruption was heard over 3,000 miles away. Scientists estimate that the blast had reached 172 decibels. By comparison, the decibel record at the Seattle Seahawks stadium reached 137.6 decibels. Also, 150 decibels are enough to rupture human eardrums. The sound waves from the eruption circled the Earth seven times. They were recorded on barometers as pressure spikes.

The eruption was equivalent to 200 megatons of TNT, which is about 13,000 times the power of the Hiroshima atomic bomb. Tsunamis were seen up to 120 feet, which devastated coastal towns and villages along Java and Sumatra. About 40,000 people were killed from the effects of the eruption, mainly from tsunamis. The force of the Krakatoa event caused about two-thirds of the island to collapse into the sea.

Ash and sulfur dioxide that were sent about 50 miles up into the atmosphere ultimately lowered the global temperature by 2 degrees Fahrenheit several years after the eruption. It led to vivid red and orange sunsets across the globe and inspired paintings, including “The Scream” by Edvard Munch. Observers also reported blue suns and green moons.

A recent study from Princeton University, which was published in Nature Geoscience, reported that major volcanic eruptions have also created distinct patterns of flooding depending on the location of the event. For example, when an eruption occurs in one hemisphere, flooding will often decrease in that hemisphere. However, the other hemisphere will likely have increased flooding, but mainly in tropical regions.

The study also indicates that volcanic plumes that affect both of the planet’s hemispheres at the same time will decrease flooding in the tropics, but the normally dry regions will have an increase in floodwaters. The research was based on three major eruptions that included the 1902 eruption of Santa Maria in Guatemala, the 1963 eruption of Agung in Indonesia, and the 1991 explosion of Mt. Pinatubo.

If one is looking to see a recent volcanic eruption, there has been some spectacular footage online of Hawaii’s Kilauea volcano that erupted again last Friday. The eruption sent lava about 100 feet into the air and scientists from the U.S. Geological Survey were able to capture some amazing footage.

The Kilauea volcano is one of the most active in the world. Since December 2024, the volcano has erupted 31 times as of late last week. The recent eruption did not threaten homes in the area as the lava was contained within the summit crater.

The most destructive and explosive volcanoes are the ones that are classified as stratovolcanoes. Hawaiian volcanoes are not the explosive type, but there have been fountains reported as high as 1,000 feet. Scientists say that this recent episode of lava fountains is the fourth one in 200 years. Back in 1983, there were 44 sessions of the fountains of lava. The other events happened in 1959 and 1969.

One of the active volcanoes near our region is about a mile underwater and approximately 300 miles off the U.S. western coastline. The Axial Seamount volcano has erupted three times since 1998. Based on recent activity, scientists believe another eruption is very likely before the end of this year. Their forecast is based on the hundreds of small earthquakes near the volcano. In June 2025, there were over 2,000 earthquakes in a single day. This type of volcano is not a threat to the public as it’s very deep underwater and not the explosive type.

In terms of our local weather, more 90-degree weather is expected through the end of the week with cooler readings and a chance of rainfall later next week. There are indications that September will have moisture totals near to above normal levels across the Spokane and Coeur d’Alene regions.

We ended last month with only 0.25 inches of rain at Cliff’s station in Coeur d’Alene, well below the August normal of 1.23 inches. At the Spokane International Airport, only 0.06 inches was measured in August.

According to the latest U.S. Drought Monitor, northern and central Idaho are currently experiencing severe to extreme drought conditions. The Spokane and Coeur d’Alene regions are listed in severe drought, but close to extreme conditions.

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Contact Randy Mann at [email protected].