There is something special and awe-inspiring about watching new land form. This is what is now happening in Hawai’i as its Kīlauea volcano erupts. Lava is reaching the ocean and building land while producing spectacular plumes of steam. These eruptions are hugely important for the creation of new land. But they are also dangerous. Where the lava meets the ocean, corrosive acid mist is produced and glass particles are shattered and flung into the air. Volcanic explosions can also hurl lava blocks hundreds of metres and produce waves of scalding hot water.
At Kīlauea, lava is erupting from a line of vents on the volcano’s flanks, and is moving downslope to the edge of the island, where it enters the ocean. This is a process that has been witnessed many times at Hawai’i and other volcanic islands. And it is through many thousands of such eruptions that volcanic islands like Hawai’i form.
The new lava being added to Hawai’i by this latest Kīlauea eruption replaces older land that is being lost by erosion, and so prolongs the island’s lifespan. In contrast, older islands to the north-west have no active volcanoes, so they are being eroded by the ocean and will eventually disappear beneath the waves. The opposite is happening to the south-east of Hawai’i, where an underwater volcano (Lōʻihi Seamount) is building the foundations of what will eventually become the next volcanic island in this area.
How lava gets to the ocean at Hawai’i
The lava erupting from the current Kīlauea vents has a temperature of roughly 1150 degrees °C, and has a journey of between 4.5km and 5.5km to reach the ocean. As this lava moves swiftly in channels, it loses little heat and so it can enter the ocean at a temperature of over 1000 degrees°C.
What happens when lava meets the ocean?
We are witnessing one of the most spectacular sights in nature – billowing white plumes of steam (technically water droplets) as hot lava boils seawater. Although these billowing steam clouds appear harmless, they are dangerous because they contain small glass shards (fragmented lava) and acid mist (from seawater). This acid mist known as “laze” (lava haze) can be hot and corrosive. If anyone goes to near it, they can experience breathing difficulties and irritation of their eyes and skin.
Apart from the laze, the entry of lava into the ocean is usually a gentle process, and when steam is free to expand and move away, there are no violent steam-driven explosions.
But a hidden danger lurks beneath the ocean. The lava entering the sea breaks up into blobs (known as pillows), angular blocks, and smaller fragments of glass that form a steep slope beneath the water. This is called a lava delta.
A newly formed lava delta is an unstable beast, and it can collapse without warning. This can trap water within the hot rock, leading to violent steam-driven explosions that can hurl metre-sized blocks up to 250 metres. Explosions occur because when the water turns to steam it suddenly expands to around 1,700 times its original volume. Waves of scalding water can also injure people who are too close. People have died and been seriously injured during lava delta collapses
So, the ocean entry points where lava and seawater meet are doubly dangerous, and anyone in the area should pay careful attention to official advice on staying away from them.
What more can we learn from these eruptions?
Once lava deltas have cooled and become stable they represent new land. Studies have revealed that lava deltas have distinctive features, and this has enabled volcanologists to recognise lava deltas in older rocks.
Remarkable examples of lava deltas have been discovered near the top of extinct volcanoes (called tuyas) in Iceland and Antarctica. These deltas can only form in water and the only plausible source of this water in this case is melted ice. This means that these volcanoes had melted water-filled holes up to 1.5km deep in ice sheets, which is an astonishing feat. In fact, these lava deltas are the only remaining evidence of long-vanished ice sheets.
It is a privilege to see these incredible scenes of lava meeting the ocean. The ongoing eruptions form part of the natural process that enables beautiful volcano islands like Hawai’i to exist. But the creation of new land here can also bring danger to those who get too close, whether it be collapsing lava deltas or acid mist.
The Trump administration is clashing with conservation groups and others over protection for the greater sage grouse (Centrocercus urophasianus), a bird widely known for its dramatic mating displays. The grouse is found across sagebrush country from the Rocky Mountains on the east to the Sierra and Cascade mountain ranges on the west.
This region also contains significant oil and gas deposits. The Trump administration is revising an elaborate plan developed under the Obama administration that sought to steer energy development away from sage grouse habitat. Conservation groups are suing in response, arguing that this shift and accelerated oil and gas leasing threaten sage grouse and violate several key environmental laws.
This battle is the latest skirmish in a continuing narrative over management of Western public lands. Like its Republican predecessors, the Trump administration is prioritizing use of public lands and resources over conservation. The question is whether its revisions will protect sage grouse and their habitat effectively enough to keep the birds off of the endangered species list – the outcome that the Obama plan was designed to achieve.
Sage grouse under siege
Before European settlement, sage grouse numbered up to 16 million across the West. Today their population has shrunk to an estimated 200,000 to 500,000. The main cause is habitat loss due to road construction, development and oil and gas leasing.
More frequent wildland fires are also a factor. After wildfires, invasive species like cheatgrass are first to appear and replace the sagebrush that grouse rely on for food and cover. Climate change and drought also contribute to increased fire regimes, and the cycle repeats itself.
Concern over the sage grouse’s decline spurred five petitions to list it for protection under the Endangered Species Act between 1999 and 2005. Listing a species is a major step because it requires federal agencies to ensure that any actions they fund, authorize or carry out – such as awarding mining leases or drilling permits – will not threaten the species or its critical habitat.
In 2005 the U.S. Fish and Wildlife Service declared that an ESA listing for the sage grouse was “not warranted.” These decisions are supposed to be based on science, but leaks revealed that an agency synthesis of sage grouse research had been edited by a political appointee who deleted scientific references without discussion. In a section that discussed whether grouse could access the types of sagebrush they prefer to feed on in winter, the appointee asserted, “I believe that is an overstatement, as they will eat other stuff if it’s available.”
In 2010 the agency ruled that the sage grouse was at risk of extinction, but declined to list it at that time, although Interior Secretary Ken Salazar pledged to take steps to restore sagebrush habitat. In a court settlement, the agency agreed to issue a listing decision by September 30, 2015.
Negotiating the rescue plan
The Obama administration launched a concerted effort in 2011 to develop enough actions and plans at the federal and state level to avoid an ESA listing for the sage grouse. This effort involved federal and state agencies, nongovernmental organizations and private landowners.
California, Colorado, Idaho, Montana, Nevada and Wyoming all developed plans for conserving sage grouse and their habitat. The U.S. Forest Service and Bureau of Land Management revised 98 land use plans in 10 states. And the U.S. Department of Agriculture provided funding for voluntary conservation actions on private lands.
In 2015 Interior Secretary Sally Jewell announced that these actions had reduced threats to sage grouse habitat so effectively that a listing was no longer necessary. A bipartisan group of Western governors joined Jewell for the event. But despite the good feelings, some important value conflicts remained unresolved.
Notably, the plan created zones called Sagebrush Focal Areas – zones that were deemed essential for the sage grouse to survive – and proposed to bar mineral development on 10 million acres within those areas. Some Western governors, such as Butch Otter of Idaho, viewed this element as a surprise and felt that it had been dropped on states from Washington, without consultation.
The Trump administration wants to cancel creation of Sagebrush Focal Areas and allow mining and energy development in these zones. Agency records show that as Interior Department officials reevaluated the sage grouse plan in 2017, they worked closely with representatives of the oil, gas and mining industries, but not with environmental advocates.
Can collaboration work?
If the Trump administration does weaken the sage grouse plan, it could have much broader effects on relations between federal agencies and Western states.
Collaboration is emerging as a potential antidote to high-level political decisions and endless litigation over western public lands and resources. In addition to the sage grouse plan, recent examples include a Western Working Lands Forum organized by the Western Governors’ Association in March 2018, and forest collaboratives in Idaho that include diverse members and work to balance timber production, jobs and ecological restoration in Idaho national forests.
There are two key requirements for these initiatives to succeed. First, they must give elected and high-level administrative appointees some cover to support locally and regionally crafted solutions. Second, they have to prevent federal officials from overruling outcomes with which they disagree.
When the U.S. Fish and Wildlife Service announced in 2015 that an endangered listing for the sage grouse was not warranted, the agency committed to revisit the bird’s status in 2020. To avoid having to list the grouse as endangered, the Trump administration must provide enough evidence and certainty to justify a decision not to list, as the Obama administration sought to do. If Interior changes land management plans and increases oil and gas leasing, that job could become harder. It also is possible that Congress might prohibit a listing.
Finding a lasting solution will require the Trump administration to collaborate with states and other stakeholders, including environmental advocates, and allow local land managers to do the same. Then, whatever the outcome, it cannot reverse their efforts in Washington. As Matt Mead, Wyoming’s Republican governor, warned in 2017, “If we go down a different road now with the sage grouse, what it says is, when you try to address other endangered species problems in this country, don’t have a collaborative process, don’t work together, because it’s going to be changed.”
Over the past few weeks we’ve seen increasingly spectacular images reported in the news of the ongoing eruption at Kilauea volcano, on the Pacific island of Hawai’i.
These have been tempered by reports of growing destruction, with houses and infrastructure bulldozed, buried or burned by lava flows.
Yet Kilauea is one of the world’s most active volcanoes, and has been erupting continually since 1983. So what has triggered this sudden change in activity, threatening homes and livelihoods? The answer relates to what is happening beneath the volcano.
Activity at Kilauea is driven by the buoyant upwelling of a plume of hot mantle, which provides the heat to generate magma beneath the volcano. This magma has the potential to erupt from several different locations, or vents, on the volcano.
Typically, the crater at the summit of the volcano is where eruptions are expected to occur, but the geology of Kilauea is complex and a rift on the eastern side of the volcano also allows magma to erupt from its flanks.
Over the past decade both the summit crater and a vent on the eastern rift, called Pu’u O’o, have been continually active. The summit crater has hosted a lava lake since March 2008.
Lava lakes are relatively rare features seen at only a handful of volcanoes around the world. The fact that they do not cool and solidify tells us that lava lakes are regularly replenished by fresh magma from below.
In contrast, Pu’u O’o, 18km east of the summit crater, has been pouring out lava flows since 1983. In the first 20 years of this eruption, 2.1km³ of lava flows were produced, equivalent in volume to 840,000 Olympic swimming pools. All of this tells us that Kilauea volcano regularly receives lots of magma to erupt.
Over the past three weeks activity at Pu’u O’o has stopped, while a series of fissures has opened roughly 20km further east in a subdivision known as Leilani Estates.
This area was previously affected by lava flows in 1955.
To date, 23 fissures have opened, starting off simply as cracks in the ground, with some developing into highly active vents from which significant lava flows are forming.
Meanwhile, at the summit of the volcano, the lava lake has drained from the crater, sparking fears of more explosive eruptions, as draining magma interacts with groundwater.
Satellite instruments and high-resolution GPS are being used to monitor changes in the shape of the volcano and have found that the summit region is deflating, while the lower east rift zone, where new fissures have opened in recent days, is inflating.
The magma reservoirs that feed eruptions on Kilauea can be imagined as balloons, which grow when they are filled and shrink when they are emptied. Deflation at the summit, combined with observations that the lava lake has drained (at a rate of up to 100m over two days!), suggest that the magma reservoir feeding the summit is emptying.
Where is the magma going? Observations of ground inflation around the newly opened fissures to the east indicate that the magma is being diverted down the east rift and accumulating and erupting there instead.
Exactly what has caused this rerouting of the magma is still not clear. A magnitude 6.9 earthquake occurred in the area on May 4 and this may have opened a new pathway for magma to erupt, influencing the geometry of the lower east rift zone.
Lessons for the future
By combining measurements from Kilauea of ground deformation, earthquake patterns and gas emissions during the current eruption, with observations of the lava that is erupted, volcanologists will be able to piece together a much clearer picture of what triggered this significant change in eruption over the past few weeks.
This knowledge will be crucial in planning for future eruptions, both at Kilauea and at other volcanoes.
Eruptions from the flanks of a volcano can pose a much more significant hazard for the local population than those from a volcano’s summit, as many more people live in the areas that are directly affected.
This has been amply displayed over the past few weeks on Kilauea by the fissures opening in people’s gardens and lava flows destroying homes and infrastructure.
But Kilauea is not the only volcano to have flank eruptions. For example, lava flows famously emerged from the lower slopes of Mt Etna in 1669, destroying villages and partially surrounding the regional centre of Catania, on the east coast of Sicily, Italy.
Lessons learned from the current eruption of Kilauea can equally be applied to other volcanoes, like Etna, where more densely populated surroundings mean that the hazards posed by such an eruption would be even greater.