Using Bombs To Avert Lava Flows

[EnolaGaia]

Sending in the bombers to avert a cataclysm isn't a trope that began with 1950s science fiction movies.

When Mauna Loa erupted in 1935 and generated lava flows threatening the town of Hilo the US Army tried bombing the lava tubes supplying the upwelling magma to avert what seemed to be an imminent disaster.

The Army commander who authorized the bombing? One George S. Patton ...

Hawaii’s volcanoes: How George S. Patton took on the lava with bombs

In December 1935 the residents of Hilo, Hawaii, were in a full-blown panic. Weeks earlier, Mauna Loa had erupted. The “glowing lava” cast an eerie red glow on the sky, the Associated Press reported at the time. There were at least five “lava rivers,” and one of them was advancing rapidly toward the town, destroying everything in its path.

Unlike the smaller communities being threatened by Kilauea’s recent eruption, Hilo was, by Hawaii’s standards, a major town. Some 15,000 residents, along with their homes and businesses were threatened. ...

Just days before Christmas the situation became dire, according to the U.S. Geological Survey. The lava was advancing about one mile per day and scientists feared it would soon reach the Wailuku River, Hilo’s main water source. At that rate, it would reach Hilo in less than 20 days.

Volcanologist Thomas Jaggar, founder of the Hawaiian Volcano Observatory, realized there was only one thing that could be done to protect Hilo. He had to stop the flow of molten rock, and he had a plan to do it: Bomb the volcano.

In theory and perhaps in the boundless American imagination, the idea makes sense. Blowing up the natural tubes within the volcano that carry the lava could disrupt its flow.

After all, humans had been battling nature for centuries, diverting rivers, clearing and burning forests and carving paths through mountain ranges. In Europe, there were even accounts of temporarily redirecting lava flows using barricades.
But bombing a volcano had never been tried before.

Jaggar needed help, so he contacted the U.S. Army Air Corps, stationed in Oahu, about 200 miles away. Enter a lieutenant colonel named George S. Patton.

Years before gaining fame as the World War II general who helped liberate Germany from Nazi forces, Patton was given the responsibility of orchestrating the first-ever aerial bombing of a volcano ...

On Dec. 27, 1935, 10 Army bombers, then biplanes with cloth wings, set out to defeat nature, according to Historic Wings, an online aviation magazine. Each plane carried two 600-pound demolition bombs. ...

The planes dropped 20 bombs on Mauna Loa that day, five landed directly in the lava flow, creating giant craters that were quickly filled by the molten rock. The other bombs missed and one even turned out to be a dud. ...

About a week later, on Jan. 2, the lava stopped. Jaggar was jubilant.

“The experiment could not have been more successful; the results were exactly as anticipated,” Jaggar told the New York Times.

While Jaggar was certain his plan had worked, other scientists were less confident. ...

FULL STORY: https://www.washingtonpost.com/news...ow-george-s-patton-took-on-the-lava-and-lost/

 

[EnolaGaia]

This 2017 USGS article describes the skepticism regarding Jaggar's claim that the bombing actually stopped the lava flow.

Volcano Watch - Did aerial bombing stop the 1935 Mauna Loa lava flow?

A widely-held belief is that Thomas Jaggar, founder of the Hawaiian Volcano Observatory, was able to stop a Mauna Loa lava flow in 1935. But is it true?

... Jaggar publicly praised the Army for its responsiveness and technical accuracy in delivering the bombs to his selected targets. In turn, Jaggar was praised for his successful experiment and saving Hilo.

What is not widely known is that a USGS geologist, Harold Stearns, was on board the last plane to deliver bombs to Jaggar's targeted areas. Stearns had been mapping the geology and water resources of Maui volcanoes. But when he heard about the plan to bomb the lava flow on Mauna Loa, he traveled to Hilo to see if he could fly with the Army.

Stearns got his chance. At 12:40 p.m. on December 27, his plane dropped two 600-pound bombs (each with 300 pounds of TNT), but they hit a few hundred feet from their target. Jaggar himself watched the bombing through a telescope from the base of Mauna Kea.

Assessing Jaggar's bombing goals, Stearns said, "The tube walls look 25 to 50 feet high and deep in the flow so that I think there would be no change of breaking the walls. The lava liquid is low. The damming possibility looks effective but the target is too small."

Following up with a letter to Jaggar in January 1936, Stearns questioned the effectiveness of the bombing.

Jaggar wrote back that later examination of the flow's source showed that "This channel was broken up by the bombing and fresh streams poured over the side of the heap…. I have no question that this robbing of the source tunnel slowed down the movement of the front…. The average actual motion of the extreme front … for the five days after the bombing was approximately 1000 feet per day. For the seven days preceding the bombing the rate was one mile per day." ...

Stearns remained unconvinced. In his 1983 autobiography, he wrote about bombing the Mauna Loa flow: "I am sure it was a coincidence…."

Jaggar's boss at the time, Hawaii National Park Superintendent E.G. Wingate, was also skeptical.

The day after the bombing, Wingate wrote to the Army commanders, "Though we are as yet unable to determine what effect the airplane bombardment achieved … I feel very doubtful that it will succeed in diverting the flow. Therefore, I am … reconnoitering the flow region and will try to locate a feasible spot on the ground where a land expedition might successfully attack the flow channel by dynamiting or other methods."

In Wingate's December 1935 report, he summarized the effort: "Just what part the bombardment had in stopping the lava flow the superintendent is not qualified to say. Certainly the facts are most interesting and Dr. Jaggar believes the experiment to have played a definite part."

Modern thinking mostly supports Stearns' conclusion. Whether or not the bombing stopped the 1935 Mauna Loa lava flow remains a controversial topic today.

FULL STORY: https://www.usgs.gov/center-news/volcano-watch-did-aerial-bombing-stop-1935-mauna-loa-lava-flow

 

[EnolaGaia]

The abstract from this 1980 research report:

Diversion of lava flows by aerial bombing — lessons from Mauna Loa volcano, Hawaii
J. P. Lockwood & F. A. Torgerson
Bulletin Volcanologique volume 43, pages727–741(1980)

... discusses the results and prospects of aerial bombing to stem lava flows, based on the 1935 and subsequent attempts and tests.

... Explosives were first suggested as a means to divert lava flows threatening Hilo, Hawaii during the eruption of 1881. They were first used in 1935, without significant success, when the Army Air Force bombed an active pahoehoe channel and tube system on Mauna Loa’s north flank. Channel walls of a Mauna Loa flow were also bombed in 1942, but again there were no significant effects. The locations of the 1935 and 1942 bomb impact areas were determined and are shown for the first time, and the bombing effects are documented. Three days after the 1942 bombing the spatter cone surrounding the principal vent partially collapsed by natural processes, and caused the main flow advancing on Hilo to cease movement. This suggested that spatter cones might be a suitable target for future lava diversion attempts.

Because ordnance, tactics, and aircraft delivery systems have changed dramatically since 1942, the U.S. Air Force conducted extensive testing of large aerial bombs (to 900 kg) on prehistoric Mauna Loa lavas in 1975 and 1976, to evaluate applicability of the new systems to lava diversion. Thirty-six bombs were dropped on lava tubes, channels, and a spatter cone in the tests, and it was verified that spatter cones are especially fragile. Bomb crater size (to 30 m diameter) was found to be inversely related to target rock density, with the largest craters produced in the least dense, weakest rock. Bomb fuze time delays of 0.05 sec caused maximum disruption effects for the high impact velocities employed (250 to 275 m/sec).

Modern aerial bombing has a substantial probability of success for diversion of lava from most expected types of eruptions on Mauna Loa’s Northeast Rift Zone, if Hilo is threatened and if Air Force assistance is requested. The techniques discussed in this paper may be applicable to other areas of the world threatened by fluid lava flows in the future.

SOURCE: https://link.springer.com/article/10.1007/BF02600367

 

[EnolaGaia]

A hiker recently discovered two unexploded bombs from the 1935 lava diversion attempt ...

Hiker finds bombs dropped into Mauna Loa volcano in 1935

In late February, a hiker on Hawaii's Big Island stumbled across two unexploded bombs on the flank of the Mauna Loa volcano. Those bombs, it turns out, were the remnants of a 1935 attempt to divert a lava flow.

Whether the "bomb the volcano" strategy worked is a matter of some debate, according to a new blog post by the Hawaiian Volcano Observatory (HVO). The lava flow did begin to slow the next day, and the man whose idea the bombing was claimed victory. Scientists at the time and today, though, believe the slowing flow was almost certainly a coincidence.

The two rusty bombs were found by adventurer Kawika Singson, who was hiking on Mauna Loa's lava fields on Feb. 16 and stumbled across the bombs inside a lava tube, according to West Hawaii Today. Hawaii has a history of trying to bomb lava flows, according to the newspaper: The strategy was tried in 1935 and 1942.

The bombs Singson found, though, were from the 1935 attempt, according to HVO. They are small "pointer bombs," which contain only a small charge and were used for aiming and targeting a set of 20 MK I demolition bombs, each of which contained 355 pounds (161 kilograms) of TNT. ...

FULL STORY: https://www.livescience.com/mauna-loa-bomb-found.html