The Palmdale Bulge: A Geo-Crisis That Likely Never Existed

By Erik Klemetti | September 19, 2018 1:12 pm
September 2006 MODIS image of southern California taken by the Aqua satellite. NASA Earth Observatory.

September 2006 MODIS image of southern California taken by the Aqua satellite. NASA Earth Observatory.

The revolution in how we survey and image the surface of the Earth has had profound impacts on the geosciences. This shouldn’t be a shock to anyone as that’s what geoscientists do — study the Earth — and as we get more and better data on the planet and its surface, the better our understanding will become (and the more questions we can ask). Few technological leaps have been more important to geosciences than satellite imaging of the Earth.

That is more than just taking cool pictures of the planet, but also collecting location and elevation data of the surface … and being able to do so in sub-centimeter precision and repeatedly over intervals of days (or less). Combine that with land-based tools like LIDAR (Light Detection and Ranging), and suddenly we can notice very small changes in the Earth’s surface. Dump all this data in a geographic information system (GIS) and we can really start picking apart almost every up and down and slide and whatever comes along. Add high-powering computing to model the physical processes and the geosciences of 2018 would look like straight up science fiction to a geologist from 1975.

Oh, but as that implies, it wasn’t always so good. Before this level of precision and accuracy in mapping the Earth’s surface, geoscientists had to rely on tools like optical leveling, tilt-meters and other more analog methods for seeing how the Earth’s surface might be changing. This is not to say that amazing maps weren’t made, but they took a lot of time and people-power to construct … and was we’ve found, they weren’t always right.

That gets us to the Palmdale Bulge.

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

What is the Evidence for Hurricanes in the Distant Past?

By Erik Klemetti | September 12, 2018 9:04 am
Aqua MODIS image of Hurricane Florence, seen on September 11, 2018. NASA.

Aqua MODIS image of Hurricane Florence, seen on September 11, 2018. NASA.

Hurricanes are massive meteorological events and, as we’ve seen recently in Puerto Rico, enormous humanitarian disasters. Yet, on a geologic timescale, massive storms like hurricanes and typhoons are ephemeral moments that are surprisingly difficult to read in the rock record, even if they seem like such powerful forces when they occur. Right now, Hurricane Florence is bearing down on the  Carolinas and it makes me wonder, what evidence could we expect to find for the hurricane 100, 1,000 or 10,000 years in the future?

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Five Things All College Students Should Know About the Earth

By Erik Klemetti | August 28, 2018 2:13 pm
The Horn of Africa seen from the International Space Station in January 2015, taken by ESA astronaut Samantha Cristoforetti. NASA.

The Horn of Africa seen from the International Space Station in January 2015, taken by ESA astronaut Samantha Cristoforetti. NASA.

So, another school year starts Thursday (for me) and I thought I’d offer a list of 5 things all college students should know about the Earth, whether they take a geology classes or not (but you really should take at least one).

#1 The Earth is 4.54 billion years old (give or take a few million years)

This is “long history”. About 4.54 billion years ago, the Earth was formed out of the pile of debris and gases that surrounded our just-born Sun. How do we know this? By determining the age of meteorites that match the composition of the early solar system using the isotopes produced by radioactive decay. We can find some evidence of the first minerals produced in the early Earth by dating zircon at the Jack Hills in Australia, and they reach back to about 4.4 billion years ago. Modern Homo sapiens have only been around for a whopping 0.004% of the history of our planet.

#2 Rocks record the evidence of evolution of life on Earth

Speaking of when Homo sapiens arrived on the scene, the rocks of Earth contain all the evidence for evolution as the driving mechanism for the diversity of life on Earth. Since life appeared ~3.8 billion years ago, rocks have been capturing a long (and somewhat incomplete) record of organisms that existed on land and in the seas. It is this “long history” that is needed to really appreciate how life has changed to meet the demands of a changing planet.

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Venezuela Rocked By Large Earthquake

By Erik Klemetti | August 21, 2018 7:01 pm
Map of shaking felt by the M7.3 earthquake in Venezuela on August 21, 2018. USGS.

Map of shaking felt by the M7.3 earthquake in Venezuela on August 21, 2018. USGS.

Venezuela was hit by a M7.3 earthquake today, causing extensive damage across the northern part of the country as well as nearby Trinidad & Tobago. Shaking was felt as far away at Bogotá, Martinique and Guyana, thousands of kilometers from the earthquake’s epicenter. This temblor may have been the largest earthquake to strike Venezuela since a M7.7 hit off of Caracas in 1900.

Video and images of the earthquake have quickly found their way to Twitter, so here are some examples (special thanks to Austin Elliot for some of these links):

The depth of the earthquake meant the shaking was felt widely across the region and from the looks of it, there was some sustained shaking but that depth might also mean that massive destruction was avoided. Some reports suggest that only minor to moderate damage was seen (see below) in cities relatively close to the epicenter. No injuries have been reported so far, however, news is slow to come out of the country due to its current political crisis

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Wilderness vs. Monitoring: The Controversy of a New Seismic Network at Glacier Peak

By Erik Klemetti | August 19, 2018 3:34 pm
Glacier Peak in Washington. Wikimedia Commons.

Glacier Peak in Washington. Wikimedia Commons.

One of the most potentially dangerous volcanoes in the Cascades is Glacier Peak in Washington. It produced the one of the largest eruptions in the past 20,000 years in this volcanic range that spans from British Columbia to California. Multiple eruptions around 13,500 years ago spread ash all the way into Montana. Over the last 2,000 years, there have been multiple explosive eruptions that have impacted what became Washington state and beyond. Put on top of that the many glaciers on the slopes of Glacier Peak that could help form volcanic mudflows (lahars) during a new eruption, and you can see that Glacier Peak is a real threat.

Yet, even with this hazard posed by the volcano, there is very little in the way of monitoring equipment on the volcano. Currently, there is a lone seismometer on Glacier Peak to measure earthquakes, one of the most important pieces of information needed to monitor volcanoes. A single seismometer is better than no seismometer, but it can only give us so much information. Without a network of at least 3 seismometers (a“seismic network”), we can really only measure if earthquakes are occurring at the volcano and not exactly where and how far beneath the volcano the temblors are happening. This is what is installed at a truly restless volcano like Mount St. Helens.

These two pieces of information — location and depth — are vital for understanding what might be happening at Glacier Peak if any earthquake swarm were to happen. Otherwise, we might have difficulty differentiating between earthquakes happening due to fault motion near the volcano or shallow changes in the hydrothermal system in the volcano rather than magma moving into the volcano from deep below.

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Is the Kīlauea Eruption Winding Down?

By Erik Klemetti | August 14, 2018 9:54 am
The steaming cone at Fissure 8 with some small pockets of molten lava in the main vent area. Taken August 12, 2018. USGS/HVO.

The steaming cone at Fissure 8 with some small pockets of molten lava in the main vent area. Taken August 12, 2018. USGS/HVO.

It has been awhile since I updated on the lower East Rift Zone eruption on Hawaii’s Kīlauea. Well, it appears that the eruption is slowing down significantly. The fountaining at the Fissure 8 cone has stopped (see above) and the lava lake that formed there has gotten sluggish and sticky. Does this mean we’re seeing the end of the eruption that has paved over so many homes and added to the Big Island? That is hard to say with any certainty at this point.

There are still dribbles of lava making it to the ocean entry between the Kapoho Bay and Ahalanui, meaning that there is still some lava being fed into the lava tube system that has formed, all being fed by Fissure 8. However, that might be merely lava making its way through the system, so the USGS is watching closely to see if the ocean entries end altogether with this waning activity.

The earthquakes and collapses at the summit seem to have slowed down sharply as well. A month ago, the summit was seeing dozens of small to moderate earthquakes each day, but now only 3 earthquakes struck on the summit on August 13. Combine that with the lowest sulfur dioxide emissions measured on Kīlauea in a decade, and all in all, it seems that something has changed over the last week.

Now, it would be easy to say that the eruption is ending, but it might not be that simple. The lack of vigorous eruptions, the low sulfur dioxide, the settling of the summit earthquakes, they all point to the idea that there is less magma moving in the system underneath Kīlaeau at this moment. However, when you look at eruptions like this that have happened around the world, they can wax and wane, so this brief pause might be just that: a pause. It will take likely months of these conditions before the Hawaii Volcano Observatory would declare this eruption as “over”.

CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Check Out How the 2018 Eruption Has Changed at Kīlauea’s Summit

By Erik Klemetti | July 30, 2018 7:30 am
Kīlauea's summit seen on a July 28, 2018 overflight, showing the deep new crater. USGS/HVO.

Kīlauea’s summit seen on a July 28, 2018 overflight, showing the deep new crater. USGS/HVO.

The eruption at Kílauea has almost reached 3 months and in a sense, this eruption was a two-for-the-price of one. Most of the attention has been on the lava flows on the lower East Rift zone and rightly so. Those lava flows are the largest eruption in historic times at the Hawaiian volcano and have destroyed hundreds of homes, along with permanently altering parts of the coast. However, even after the really big explosions died down at the summit, the big changes there have continued.

Every 10-20 hours (or so), the summit experiences another explosion that releases about the same energy has an ~M5 earthquake would release. These explosions — 58 so far — are all happening because the summit is still subsiding — sinking into the ground. This slow collapse to form another caldera inside the pre-existing Kīlauea caldera has been going since the lower East Rift zone started and is likely cause by all that magma leaving the summit, pulling support out from the summit. Even between explosions, the summit area experiences dozens of small earthquakes per hour. As long as the lower East Rift zone eruption continues, we might expect the collapse of the summit to continue (and you can watch it on the HVO webcams).

So, what has changed? This collapse started around the lava lake that used to reside in the Halema’uma’u Crater. That lava lake formed in 2008 and last almost exactly a decade. Since the lava lake drained in May, the Crater has collapsed, taking some of the larger caldera floor with it.

Check out this image of the Kīlauea summit area in 2003 (below).

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Earthquake Swarm Off the Coast of Oregon and California

By Erik Klemetti | July 25, 2018 9:48 am
(Credit: Lynn Yeh/Shutterstock)

(Credit: Lynn Yeh/Shutterstock)

One thing that many people in the Pacific Northwest are holding their breath for is “The Big One” — the next recurrence of a massive earthquake in the Cascadia Subduction zone. This earthquake could be greater than a magnitude 8 and cause immense damage to cities like Portland, Seattle and Vancouver. This hypothetical earthquake could even potentially trigger a tsunami that will cross the Pacific Ocean just like a similar temblor in 1700 did when waves washed ashore in Japan. It is a serious threat that could happen next week … or in 200 years.

Sources of potential earthquakes in the Cascadia subduction zone. The Big One will be similar to the 1700 earthquake. USGS.

Sources of potential earthquakes in the Cascadia subduction zone. The Big One will be similar to the 1700 earthquake. USGS.

With all that being said, not all earthquakes in the Pacific Northwest are the same. The Big One will be generated by the stress built up as the Juan de Fuca plate off the coast of Oregon, Washington, California and British Columbia slides underneath North America (see above). The plates can stick, creating stress that is sometimes released as giant earthquakes (and many smaller ones). The “snapping” back of the plate can create tsunamis, just as we saw in 2004 off Indonesia and 2011 off Japan.

However, those aren’t the only earthquakes that might be felt in the Pacific Northwest. The volcanoes of Cascadia, formed from the same subduction that is going on with the Juan de Fuca plate, can generate earthquakes as magma moves underneath them. Smaller faults that are far inland and shallower than the boundary between the two plates can also accumulate stress and form earthquakes that tend to be smaller (but potentially as damaging if they were to happen under a big city).

Locations of the July 24-25, 2018 earthquake swarm off the coast of Oregon and California. USGS.

Locations of the July 24-25, 2018 earthquake swarm off the coast of Oregon and California. USGS.

The current earthquake swarm off the coast of Oregon and California (see above) is yet another way earthquakes are generated. At least 11 earthquakes that were as large as M5.6 have shaken the seafloor ~200 kilometers (125 miles) from Crescent City in California. The largest of these were weakly felt along the coast and didn’t generate any tsunami of any kind. It has definitely gotten people’s attention, but this isn’t a precursor to the The Big One.

Instead, these earthquakes are happening along part of the mid-ocean ridge where the Pacific Plate is moving away from the Juan de Fuca plate. Instead of the Big One and other earthquakes formed by plates coming together, these earthquakes were from extension — plates or parts of plates spreading away from each other. They occurred within ~40 kilometers (25 miles) of the Juan de Fuca spreading ridge, where magma rises and pushes the plates apart. So, earthquakes like these are fairly common off the North American coast.

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That Fissure Opening “Near” Yellowstone? Not a Sign of an Impending Eruption.

By Erik Klemetti | July 20, 2018 1:25 pm
The Grand Tetons in Wyoming. Pixabay.

The Grand Tetons in Wyoming. Pixabay.

Many people have pointed out to me that there is a news frenzy about “fissures opening near Yellowstone“. Now, considering that if this were happening, that would be newsworthy, I had to check it out … and with most “news” about Yellowstone, it is much ado about nothing related to the volcano in Wyoming.

Climbers in Grand Teton National Park, to the south of Yellowstone, have noticed that the cliff face at Hidden Falls and Inspiration has been breaking off due to cracks (“fissures”) on the mountain. This crack has made it very dangerous for climbers as bits of the cliff (or possibly the entire face) might come crashing down, taking climbers with it. This sort of thing happens often on exposed rock in mountain areas. They can be easily oversteepened and then gravity does its thing, bringing rock down fast. Yosemite National Park experiences this quite often and people have died in the process. That’s why Grand Teton National Park has closed the area to the public.

However, because this cracking — likely due to faulting or weathering in the Tetons — is happening in the general vicinity of the Yellowstone caldera, many in the media have wrongly connected these cracks with the volcano. Let’s get it straight right now: this is in no way a sign of impending eruption at Yellowstone.

Some sources have even tried to say things like “Grand Teton National Park sits atop the Yellowstone supervolcano“. This is just wrong. Even when you look at the footprint of the volcanic system at Yellowstone (see below), it is a massive stretch to say that the Tetons are “over” Yellowstone. The Grand Teton mountain range were formed by the stretching of North America and formed in the geologically-recent past (the last 10 million years). Yellowstone is there due to a hotspot under North America and is not the cause of the Teton range. Connected the two directly is just a gross violation of correlation (location) leading to causation (fissure formed due to the volcano … which it didn’t).

Map of the Yellowstone caldera. The Grand Tetons (and this fissure) are to the south, beyond the extent of this map. USGS.

Map of the Yellowstone caldera. The Grand Tetons (and this fissure) are to the south, beyond the extent of this map. USGS.

Even the portrayal of the fissure as “vast” is overblown. Reports say it is 100 feet long. That’s 30 meters. That is small. I realize that with the eruption in Hawaii, people are now attuned to hear “fissures” and “volcano” and jump to new conclusions that an eruption will start, but this is not the case here. There is no magma body near the surface under the Tetons — and no other signs like earthquakes or gas release. So, no eruption is coming, especially from a 30 meter fissure over 100 kilometers from Yellowstone.

Remember, always trend cautiously when you read about people saying Yellowstone is going to erupt soon. The only real source for news that the conditions at Yellowstone are changing is the USGS Yellowstone Volcano Observatory. Beyond that, 99% of all Yellowstone news that implies eruption is just an attempt to scare people into reading articles.

CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Lava Bombs from Ocean Entry Injure 23, Damage Boat in Hawaii

By Erik Klemetti | July 16, 2018 5:42 pm
The ocean entry from the Fissue 8 eruption in the lower East Rift zone of Kīlauea, seen on July 15, 2018. USGS/HVO.

The ocean entry from the Fissue 8 eruption in the lower East Rift zone of Kīlauea, seen on July 15, 2018. USGS/HVO.

News out of Hawaii today is that we have had one first major injury event related to Kīlauea’s ongoing lower East Rift Zone eruption. A tour boat sailing near the ocean entry from the Fissure 8 lava flows was struck by volcanic debris thrown by an explosion, injuring at least 23 people and tearing a hole through the roof of the boat (see below). The boat was apparently outside the 300 meter safety zone near the ocean entry (although some news reports say the boat was only 180 meters away), meaning that these explosions are throwing large lava bombs and blocks further than that!

Here is some video of the explosion that damaged the vessel:

#LeilaniEstatesEruption #KilaueaVolcano UPDATE (July 16 at 9 AM): Unbelievable footage from @IkaikaMarzo’s crew on board the @KalapanaCulturalTours lava boat captures the lava explosion that sent lava bombs (lava rock and debris) flying into the air, which landed on a tour boat that was operated by Shane Turpin. The Hawaiʻi County Fire Department has just confirmed 12 passengers were injured. We are told three people were taken by ambulance to Hilo Medical Center. Two passengers (no details on gender or age) were in stable condition. One, a woman in her 20s, is in serious condition with a fractured femur. The remaining 9 passengers drove themselves to the hospital, and the Fire Department reported their injuries were not as serious. Hawaiʻi County Fire officials say a lava bomb punctured the roof of the boat, leaving a large hole. One of the railings of the boat was also damaged. The lava tour boat returned to Wailoa Harbor in Hilo and docked near Suisan around 7 AM. #HawaiiNewsNow has learned that the state Department of Land and Natural Resources is taking the lead on this investigation, which will involve the U.S. Coast Guard as well as the county. It’s unclear how close Turpin’s tour boat was to the Kapoho lava ocean entry when the explosion happened, but eyewitnesses report the boat appeared to be “very close”. On July 11, the Coast Guard changed their mandatory safety perimeter zone around ocean entries (Kapoho and Kalea) from 100 meters to 50 meters for licensed lava tour boat operators. I spoke with #IkaikaMarzo, who says he was consulted about the change, but disagreed with it — saying he believed it was unnecessarily close. All other mariners, without explicit written permission from the Captain of the Port of Honolulu, are required to observe a mandatory 300 meter safety zone around all active lava entry point. Stay tuned to @HawaiiNewsNow for the very latest developments! As soon as I have more information, I’ll update you. #HInews #HawaiiNews #HNN #WeAreYourSource (Images courtesy @IkaikaMarzo)

A post shared by Mileka Lincoln (@milekalincoln) on Jul 16, 2018 at 12:09pm PDT

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CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs
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Rocky Planet

Rocky Planet covers all the geologic events that made and will continue to shape our planet. From volcanoes to earthquakes to gold to oceans to other solar systems, I discuss what is intriguing and illuminating about the rocks beneath our feet and above our heads. Ever wonder what volcanoes are erupting? How tsunamis form and where? What rocks can tell us about ancient environments? How the Earth might change in the future? You'll find these answers and more on Rocky Planet.
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