There is the strong tendency in humans to look for patterns, even when none exist. This is amplified by the modern effect of news media, where certain events make headlines for reasons not necessarily related to the severity of the event.
See the update below on the 7/6 earthquake in California.
We see this frequently in geology, where a news-making eruption or earthquake then starts a cascade of reports of other eruptions and earthquakes that follow, even if they aren’t disasters. This feeds into our propensity to construct patterns from things, even when one doesn’d necessarily exist. For example, when read about a bunch of geological events, it’s tempting to think: “Uh oh, the Earth must be getting more active!”
The truth is that earthquake and eruption activity does wax and wane, but over time, our planet is not “becoming more restless” than it was 100 or 1,000 or 10,000 years ago. Most earthquakes and eruptions are sprinkled randomly over time and that randomness sometimes produces clusters of events. Flip a coin 100 times and you might get 8 heads in a row, then none for another 10 tosses. That’s clustering in a random distribution.Read More
For the second time in a week, a blast from a new eruption been flung over 10 kilometers into the sky. However, unlike Raikoke in Russia, this one came from a volcano that has a well-known history of big explosions.
Ulawun, on the island of New Britain in Papua New Guinea, unleashed an eruption this morning (local time) that reached at least 13.5 kilometers (45,000 feet) high according to the Darwin Volcanic Ash Advisory Center. Himawari-8 captured a great sequence showing the growing, tan ash plume from Ulawun (below). Ash drifting out over the Pacific has now reached 19 kilometers (63,000 feet) but at least for now, the eruption looks to have ceased.Read More
It has been awhile since we’ve had an unexpected eruption, but last night Raikoke in the Kuril Islands off Russia had an impressive explosion. Most people (and volcanologists) are likely unfamiliar with this remote volcano and rightly so — only ~140 people live within 100 kilometers and the last known eruption was in 1924. However, the last two eruptions (1924 and 1778) were both VEI 4 events.
The new eruption sent a brown plume of volcanic ash through the white cloud deck. Estimates for the plume height from the Tokyo VAAC are ~13 kilometers (43,000 feet) spreading almost due east. This means that the eruption is likely prompting diversions for aircraft traveling between North America/Europe and Asia.Read More
This summer is really the summer of the Moon. As we approach the 50th anniversary of the Apollo 11 landing, many people are thinking about our past and future relationship with our celestial partner. It is the only object in space whose surface can be seen with the naked eye (without going blind … sorry Sun), yet only two dozen people have even been there. As we look back at our first visit five decades ago, it’s worth taking a moment to consider just how unique Earth’s closest neighbor is.
There are lots of moons in the solar system, so in that sense, the Moon is not unique. Some planets, like Jupiter and Saturn, have dozens upon dozens of moons that come in nearly every shape and size. In fact, every planet that has a moon of some kind has more than one … except Earth!Read More
On Sicily’s western coast, the volcano Etna decided to bring the heat for the start of summer. After a fairly quiet few months, the volcano roared back over the weekend with explosions, new fissures and long lava flows. Etna watchers will be keeping on eye on the volcano to see if this is the start of a set of major eruptions like we saw in 2013.
This is actually the second significant eruption from Etna this year. Back in February, the volcano produced lava flows that covered over 1 cubic kilometer (~250 acres) up on the southeast flank of the volcano. This was followed by some ash and splattering lava from 3 vents near the summit in May — signs that new magma was definitely very near the surface.Read More
I live in Ohio and one thing I’ve had to get used to here that I didn’t experience most places I have lived are tornadoes. This week, parts of western Ohio got hit by some big and destructive tornadoes and in total, at least 17 tornadoes were confirmed across the state. This is part of a larger tornado outbreak across the central U.S. Tornadoes are a lot like volcanic eruptions: they’ve highly destructive and nearly impossible to predict exactly when/where they will occur.
— WLWT (@WLWT) May 28, 2019
Across the U.S. each year, there is on average over 1,200 tornadoes of various sizes. Like volcanic eruptions, there is a scale to categorize tornado strength. Tornadoes form when you have cold air up high in the atmosphere and moist, warm air at the surface. Combine that with twisting winds that get stronger as you go up. So places where cold and warm airmasses meet tend to be hotbeds of tornadoes.
Whereas volcanologists talk about the Volcanic Explosivity Index (VEI) that looks at how much stuff was blasted out during an eruption, tornadoes are compared with Enhanced Fujita Scale (EF) that uses wind speed and damage. Tornadoes rank from EF0-5 as the 3-second winds increase from 65-85 mph (104-136 km/h) to over 200 mph (320 km/h). The tornado that hit Celina, Ohio was an EF3 while the even larger one near Lawrence, Kansas was an EF4.Read More
I am always amazed how much we are still discovering about massive volcanic eruptions that happened as little as a few thousand years ago. Geologically speaking, that is something that happened yesterday, yet even that small slice of time can obscure some giant volcanic events whose effects could have spread across the globe.
Two recent studies have improved our understanding of two truly enormous eruptions that happened in Central and South America. One, only 1,500 years ago, may have produced one of the tallest eruption plumes in the past 10,000 years while the other may have been one of the most voluminous blasts in that same period. In both cases, it took careful geologic field mapping and geochronology (dating) to unravel two events the likes of which we haven’t experienced in centuries.
The Earth has always been in the path of rocks from space. When the solar system was forming, the early Earth was pelted with rocks so frequently that it left the surface molten. In fact, the creation of the Moon was caused by a massive impact of a “rock”, albeit a Mars-sized rock. These days, there are many fewer impacts (thankfully) but the threat still remains that an asteroid we might not even know about yet could strike the planet. This week, as part of the 2019 Planetary Defense Conference, NASA is running a scenario where an asteroid impacts the Earth to contemplate what the results of such an impact might be today.
The Earth has many battle scars from previous impacts. These relicts of asteroids are a reminder that Earth gets hit. Many times, the craters left by an impact is erased by the Earth’s dynamic surface processes: weathering and erosion, eruptions, plate tectonics, oceans. However, some impacts are preserved due in part of their recency, size or the geologic history of the area.
Most people would think that it would be hard to hide the evidence of a massive volcanic eruption. It shouldn’t be hard to track down the source of tens of cubic kilometers of ash and debris because it should just get thicker and thicker until you reach the volcano that disgorged the mess. Yet, somehow, it isn’t that easy. We live on a geologically active planet where all the processes of weather, tectonics, volcanism and more can quickly disassemble the deposits of an eruption — even a giant one — to the point where it might be challenging to pinpoint the source.
One such example is a layer of ash found around the northern coast of the Mediterranean called the Y-3 ash. Some Y-3 ash had been dated to ~28.6 to 29.4 thousand years ago and the ash itself has a chemical composition that is a lot like one of the biggest volcanoes in the Mediterranean basin, the Campi Flegrei. Yet, although this ash can be found for thousands of miles away from the Bay of Naples (home to the Campi Flegrei), geologists had not found any matching volcanic deposits near the caldera volcano itself that could be the match to the Y-3 ash. So, what’s going on?
We know surprisingly little about seismicity (on Earth it would be earthquakes) on other planets. Although we have done a little seismology on the Moon, both “listening” for natural temblors or creating our own, beyond that, we haven’t had much luck. Sure, the 1970s Viking landers had seismometers as part of their array of instruments, but they were sitting on the deck of the landers, not placed on the ground, so almost no useful data was collected.
The newest Mars lander, InSight, is there to remedy this problem. The NASA mission landed on Mars in December 2018 with the goal of learning as much as possible about the Martian interior. Mars doesn’t have anywhere near the geologic activity of Earth. So far, we have never witnessed any volcanic activity on Mars and the most recent volcanism might have been a million years ago or more. There is no obvious flowing water on the surface of the planet save for some evidence of ephemeral springs in craters. The carbon dioxide ices at the poles do change with Martian seasons, as does the frequency and intensity of the massive dust storms — but that activity is restrained to the surface.
There is no evidence of anything like Earth’s plate tectonic system, now or possibly even in the past 3 billion years of Martian history. Evidence for that comes from the massive Martian volcano Olympus Mons, which appears to be the product of a hotspot, much like Hawai’i. However, instead of a chain of volcanoes that formed as the Pacific Plate moved over the Hawaiian hotspot, all the lava erupted from Olympus Mons appears to have piled up in one location, suggesting few moving plates like on Earth (but maybe not a complete lack of tectonics).