Eruption Begins in the Big Island's Puna District

Erupting vent of Pu'u O'o and the East Rift in 2009

The people of Hawai'i have a lot on their hands at the moment. A few months ago, someone pushed the wrong button, and the inhabitants thought for 45 minutes that they would be incinerated by North Korean bombs. Just two weeks ago, the island of Kaua'i was hit by an epic record-setting storm that dropped feet of rain and caused widespread flood damage that they are only beginning to clean up. And then tonight comes news that a new eruption is taking place on the Big Island.

Developments in the Puna District on the East Rift Zone of Kilauea (2009)

The words "volcanic eruption on the Big Island" aren't normally an extraordinary story. Kilauea has been erupting continuously since 1983, and lava flows have been emanating from Pu'u O'o in the East Rift Zone. Since 2008 the summit caldera of Kilauea has been erupting as well. The summit flow actually made news last week when the lava pit filled and overflowed into the floor of the caldera. But today's news is a bit more ominous.

Most of the activity in recent years has been in isolated parts of Hawai'i Volcanoes National Park, and along the coast where the lava has been flowing into the sea without causing major damage (but to be clear, hundreds of homes in the Kalapana District were destroyed in the early phases of the Kilauea eruption). But the Puna District lies miles east of Pu'u O'o vent, and lava flows there are relatively uncommon. There were extensive flows in 1790, 1840, 1955 and 1960. A flow in 2014 briefly threatened homes in Pahoa (see the map below). In the years since these eruptions, a thick rainforest has grown over the lava flows, hiding the evidence of their destruction. And people moved in. Housing developments proliferated on and near the older lava flows.

This week, the summit cone of Pu'o O'o collapsed and sent an unusual pink cloud of ash rising over the Puna District. Lava drained from the molten lake at the cone and began intruding underground in  the cracks and fissures of the East Rift Zone. Dozens of earthquakes heralded the movement of the magma, and cracks appeared here and there on roads in the region. And word comes tonight that a rift zone eruption has begun very close to the Leilani Estates. Evacuations have begun, and we now must wait to see how events unfold. I'm hoping that damage will be minimal.

Pu'u O'o on May 3, 2018, courtesy of the U.S. Geological Survey

I've enjoyed my visits to the Puna District. One of the most fascinating sights are the tree molds from the 1790 lava flow at Lava Trees State Park. When the lava encroached into the rainforest, it tended to freeze solid around the tree trunks, and then the lava flow subsided somewhat as it continued down the slope. The trees burned of course, but the lava maintained the shape of the trunks as empty molds.

The native Hawaiian people saw these monuments as frozen beings. Do you see the face in the mold below?

On a field trip in 2004 we spent several of our Hawaii hours in...a power plant! It's significant because it is a geothermal plant that uses the hot water emanating from magma chambers deep in the crust beneath the 1790 lava flow to provide 20% of the electrical needs of the Big Island. It is now threatened by the current activity.

The Hawaiian Islands owe their very existence to the hot magmas emanating from the Earth's mantle, but living on the Big Island entails risks related to the constant volcanic activity. Pele's whims can never be taken for granted. Active lava flows are a spectacular draw for tourists (including me whenever possible), but they can threaten those who live there.

Lava flows on the flanks of Pu'u O'o in 2009

It's been a tough couple of months for the people of Hawai'i. My heart goes out to them.

Updates from the United States Geological Survey and the Hawai'i Volcanoes Observatory can be found at: https://volcanoes.usgs.gov/volcanoes/kilauea/status.html. Emergency updates from the County of Hawai'i can be found at http://www.hawaiicounty.gov/active-alerts/.

Ocean entry of lava flows from Pu'u O'o in 2009

Volcanoes in Hawai'i: Rock Finds a Way (to destroy life)

The summit of Mauna Kea in the distance, and the forested lower slopes of Mauna Loa in the foreground

My last entry on the geological drama of Hawai'i concerned the stubbornness of life in a harsh volcanic environment, such as that which is found on the highest slopes of Mauna Loa and Mauna Kea on the Big Island of Hawai'i. I was echoing of course one of the memorable lines from the movie "Jurassic Park". As I started to review my next set of pictures from my recent trip, I realized the opposite supposition also holds true: rock finds a way (to kill life).

Lua Manu Crater on Chain of Craters Road. It formed by collapsing several hundred years ago, and was later filled with lava flows in 1974. 

Now obviously, it couldn't be clearer that lava destroys life as it flows through and burns forests. The aftermath of many a flow is a barren plain with no sign of life of any kind. In the tropical climate of Hawai'i, life returns quickly as wind and water aid in the propagation of seeds from the nearby forest. Sometimes it is bird droppings that scatter the seed and provide the first nutrients that lead to a rebirth of life. The surface of the Big Island gets made over repeatedly over the millennia.

The battle between rock and life does take unusual forms sometimes, which is what I wanted to illustrate in today's post. Basaltic lava is not always the all-consuming fiery hell we often take it to be. It may be in excess of 2,000 degrees Fahrenheit (1,100 degrees Celsius) as it flows from the vent, but when the lava encounters cold objects, the surface of the lava can freeze quickly. When the object is a tree, strange things can happen.

On the slopes of Kilauea or Mauna Loa, the most common tree is the Ohi'a, which I wrote of in the previous post. In 1974, the Keanakāko‘i flow overwhelmed an Ohi'a forest near Chain of Craters Road in Hawai'i Volcanoes National Park. The lava froze around the trunks as the trees themselves caught fire and burned away.

The resulting cavities are called tree molds, and they were spread widely in the Keanakāko‘i flow. The charcoal from the former tree can still be seen in some of the molds after forty years (below).

At times, the molds perfectly preserve the pattern of the bark, as can be seen below.

There is another odd phenomena that occurs in these events. The lava flows past the trees, solidifying around the trunk, and continuing on. It's not always obvious, but as lava flows by, the thickness can change, and the level of the flow can drop around the trees. The tree molds are left behind as towers of basalt with hollow centers (lava trees). It's actually kind of eerie to encounter such ghosts in the midst of a living forest (below), and easy to understand how ancient people considered these to be people turned to stone by the gods.

The 1974 has hundreds of these lava trees, and some take bizarre shapes, as in the case below, where a multiple-trunked tree (or a clump of several) was preserved.

It's obvious that life is slowly being reestablished on the flow, as we were surrounded by Ohi'a trees and other species at various stages of growth.

It turns out that the tree molds themselves offer a hospitable environment for life, with nutrients provided by the charcoal, and cooler wetter conditions below the surface.

The lava forests can be seen in several places. By far the easiest is at Lava Tree State Monument in the Pahoa area. It resulted from a flow in 1790, and the park offers paved accessible trails and interpretive signs. If you want to see the Keanakāko‘i ghost forest, you'll find it in the vicinity of Lua Manu Crater on Chain of Craters Road in Hawai'i Volcanoes National Park. There are no signs and no trails, so you are in for a bit more of a rugged adventure. Be prepared with water, sturdy shoes, and the other usual things you need for a wilderness outing. And...be careful while studying the ghost trees. Many are unstable and fragile and could be destroyed by a thoughtless climb or push. And having one fall on you can't possibly end well.

Scenes from a Shield: Traversing California's Biggest Volcano

Continuing on with our late September exploration of the California Cascades, we prepared to leave Lava Beds National Monument. The main paved access is from the north at Tulelake, but our interests lay to the south over the top of the biggest volcano in California: Medicine Lake Highland. MLH is a shield shaped edifice, but the history and composition of volcano suggests a complicated history that is quite distinct from shields like those in Hawaii and elsewhere. Lava Beds National Monument covers about 10% of the shield complex on the north flank. We headed up the good gravel road to the highest corner of the park where we could investigate the source of the lava flows and tubes at Mammoth Crater.

Before reaching Mammoth Crater, we stopped at Heppe Caves to catch an unusual sight: water! Very few sources of open water exist at the Lava Beds. Fracturing of the basalt allows water to seep into the ground quickly and no streams or canyons can be seen in the park. At Heppe Cave, a deep layer of ice allows a small pool of water to persist in the lowest part of the huge cavern in most years. Birds and other animals depend on the pool, despite its diminutive size.

We had gained several hundred feet from the vicinity of the park campground and visitor center, and the cooler wetter climate allowed for the growth of ponderosa pines, and to my surprise, a small aspen grove! These stunted trees are not a common sight in the area.

A few hundred yards up the road brought us to Mammoth Crater, the source of the lava flows that cover about 70% of Lava Beds National Monument (and which produced many of the lava tubes). During the eruptions, the crater would have been a lake of molten lava, spilling over in several directions. In the waning phases of the eruption, the lava drained away, leaving a pit a quarter of a mile across and several hundred feet deep.

People often think that volcanoes erupt only from their summit, but we were quite a few miles short of the summit of Medicine Lake Highland. The mountain is covered with cinder cones and lava flows that originated from vents on the flanks of the volcano.

 It took a few false starts, but I finally located the obscure track that left the main "highway" and took us to these unusual holes in the lava. Does anyone want to speculate what they might be??

The two holes above joined about two feet down. People can reach in and hold hands underground. A few of the mysterious holes are quite large and deep. The deepest sometimes have snow all summer.

Another one or two miles through the thick forest brought us to the edge of the Medicine Lake Highland caldera. It is about as wide as the Crater Lake, some four or five miles, but beyond the horizontal distance, there are few similarities. Crater Lake has cliffs that drop straight into the lake, where MLH has rounded glaciated knobs and peaks. Crater Lake has a nearly 2,000 foot deep lake, where MLH as a lake that barely makes it past 100 feet in depth. Mt. Mazama, the mountain that existed prior to Crater Lake erupted just 7,000 years ago. The eruptions that produced the caldera on MLH took places tens of thousands of years earlier.

Medicine Lake technically shouldn't exist on a mountain that notoriously sucks up all the water. It seems that the glaciers that formed on the mountaintop produced and scraped up enough clay to seal the bottom of the lake and keep the water from draining away.

It was in the low to mid forties while we stood on the shoreline, and it was drizzling. But the sign said "swimming beach", so my students, who always follow what the signs say...

 ...did just that: went swimming in a subalpine lake. I make no judgements here, but I had a bone-chilling cold day, and it didn't help to see them swimming away!

Our next stop: the last thing you would expect to see on a basaltic shield!

Weird Geology: Accretionary Wedge #34...Our Human Nightmares

Well, how about that? I was trying to figure out how to squeeze in a bizarre shot from my recent trip to Joshua Tree National Park, and the 34th Accretionary Wedge announcement drops in my mailbox, courtesy of Dana at En Tequila es Verdad:

Geology can be strange. Outrageous. Bizarre. I'm sure you've all run into formations and landscapes and concepts that have left you scratching your head. Maybe they got less weird later. Maybe they stayed strange. But however transient or permanent that weirdness was, it got weird.

So tell us about it. Hit us with the strangest stuff you've got.

I'm late to the party, but what's new?I see a lot of weird stuff in my travels, but what strikes me isn't so much the geology, but our weird response to the geology. Can you look at the rock in the picture at the beginning of the post and not see the face of monster trying to emerge from the ground? The rock results from a random process of weathering and erosion, but see it from the right angle, and the rock becomes of mythical story of beasts and human nightmares and heroes on quests. Perseus fought Medusa, who turned men to stone. Tree molds in Hawaiian lava flows were people turned to stone (above). The volcanic necks of the Four Corners region were the monsters who were vanquished by the Navajo Twins Monster Slayer and Child-Born-of-Water (below).Pareidolia is a psychological phenomenon "involving a vague and random stimulus (often an image or sound) being perceived as significant. Common examples include seeing images of animals or faces in clouds, the man in the moon or the Moon rabbit, and hearing hidden messages on records played in reverse". It's part of being human, the recognition of human faces being one of the most important skills of a newborn baby.

Of course, such things can get out of hand when we start seeing Jesus on tortillas, or faces on Mars that are obviously signs of Martian civilization (I thought it was Elvis myself). Or the Devil smiling in the smoke and ash of the Twin Towers burning (wasn't there enough evil in the hearts of the terrorists?).

The Other California: If a Tree Falls in a Forest, Will, uh...If Lava Knocks Over Tree in the Forest...?

Lava has a well-deserved reputation for destroying everything in its path, not to mention melting human beings and chasing movie heroes. What really happens when lava flows into a forest? When I traveled in Hawaii, I found out that trees actually do persist, temporarily, as the lava flows through. The trees cool the lava enough to freeze the liquid, and then the tree burns, leaving behind a gap in the shape of the tree: a tree mold.

Hawaii has a great many tree molds, but California is not totally bereft of examples. One good place to see them is on the Medicine Lake Highland, California's biggest volcano. About 12,330 years ago, a minor basaltic eruption took place just north of the caldera rim. It flowed through a Western White Pine forest for a few hundred yards, and ended. In most places the basalt was no more than 10-20 feet deep. The doomed trees burned, but the molds remained (the charcoal from the burned trees provided the material for radiocarbon dating. The molds are 10-15 feet deep, and several are big enough to climb into (see the photo above).

Snow reportedly remains in the molds for much of the summer. Bark patterns and branches are also preserved; in the photo below, a person can reach into both holes and clasp their hands about two feet down in the rock.
The molds can be seen on Forest Road 49 about 10 miles from park headquarters at Lava Beds National Monument, and 6 miles from Medicine Lake (see map below).

Source: Johnston, D.A., and Donnelly–Nolan, J.M. eds., Guides to some volcanic terranes in Washington, Idaho, Oregon, and northern California: US Geological Survey Circular 838, p 171–176

Friday's Mystery Photo Explained

I was gratified by the many responses to Friday's Mystery Photo, and all of you were partly right, in that the photo was in basalt. The picture was in fact taken at Fossil Falls near the Coso Range east of the Sierra Nevada (and south of Owens Lake). During the Pleistocene ice ages, Owens Lake filled with glacial meltwater, and spilled over into the valley to the south. The river poured over a thick basalt flow. With all manner of boulders and pebbles to work with, the swirling eddies produced a dazzling collection of huge potholes. The pothole in the picture was unusually deep and narrow, and eventually broke out into the main channel about 9 or 10 feet down. The more energetic and flexible members of our party could shimmy up the tube and climb out. I am about 15 years past being able to do it anymore!

The site is not far from the "village" of Olancha, and includes a small undeveloped campsite and restrooms. The falls area was popular with early Native Americans, with stone rings and obsidian work sites, as well as a few petroglyphs in the area. After rains, the potholes also play host to fairy shrimp, who are born, live, reproduce, and die within a period of a week or two.

Nearby Red Hill is a classic cinder cone, and numerous cinders and volcanic bombs can be found in the vicinity. The Sierra Crest provides a wonderful backdrop.

The pictures above reflect how reasonable the tree mold idea was. Tree molds form when lava flows inundate forests. The lava freezes around the tree trunks, and the trees then burn, leaving behind perfect molds. I have seen tree molds of big Ponderosa Pines on Medicine Lake Highland in northern California, and they are large enough and deep enough (10-15 feet) to climb into. The two molds in the second picture are two branches from one tree, and they merge about two feet down.

Pictures of Fossil Falls in the next post...