Lava in Hawai'i is creating new land. It also might kill you

Lava flows from Kīlauea. Image: EPA.

There is something special and awe-inspiring about watching new land form. This is what happened recently in Hawai’i as its Kīlauea volcano erupted. 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.

When lava meets the sea, new land is formed. Image: EPA.

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 vapour) as hot lava boils seawater. Although these billowing steam clouds appear harmless, they are dangerous because they contain the 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.

Pillow Lavas form underneath the ocean. Image: National Oceanic & Atmospheric Adminstration (NOAA).

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.


The ConversationIt 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.

Dave McGarvie, School of Physical Sciences, The Open University and Ian Skilling, Senior Lecturer (Volcanology), The University of South Wales.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

“The transport equivalent of the Schleswig Holstein question”: why Britain needs to reform bus funding

Look! A bus! Image: Wikimedia Commons.

Putting public money into the bus is one of the biggest bargains in transport policy, yet it has been one of the biggest losers from recent trends in transport spending. This makes little sense given the Urban Transport Group’s latest analysis, which shows that supporting bus services aligns with the policy goals of 12 of the 25 different departments in Whitehall.

And it’s not just the departments you might expect. Buses tick the boxes for the Department of International Trade because the British bus manufacturing industry has an impressive export track record. The bus meets the goals of the Department of Work & Pensions, such as providing access to opportunity. It helps out DEFRA because buses support rural economies.

And the bus supports the aims of the Department of Health and Social Care as buses promote physical activity, give older and disabled people independence and because they could play a greater role in a more efficient approach to non-emergency patient transport. In short, every single pound that supports bus services cuts congestion, while contributing to numerous wider social, economic and environment goals. Not many other modes of transport could tot up all these benefits.

But without public support for bus services, labour markets will shrink and more people will be unable to participate in the economy; skills and apprenticeships will be hit because of reduced access to further education. High street regeneration will be damaged through reduced access to town centres, and there will be increased pressure on congested road networks as bus users migrate to the car. And there’ll be public health impacts from more isolation and loneliness, and less physical activity. The young will be hit hardest. A divided society will become more divided.


Despite these risks, that hasn’t stopped all six sources of bus funding being cut back in recent years. This in turn, has given an unhelpful shove in the back to a mode which was already tumbling down the slope, plummeting towards the cliff edge in too many parts of the country.

Meanwhile, Highways England has more money that it can spend to expand inter-urban road capacity which will continue to pump more traffic into cities that don’t want it, generate more car-dependent sprawl, worsen air quality, increase carbon emissions and replace big traffic jams with even bigger traffic jams. An extra £500m a year for buses, for example, would be less than 2 per cent of the annual revenue to Treasury from fuel duty.

It’s not just the total amount of bus funding that is the problem however. Making things worse is the convoluted and uncoordinated way in which buses are funded by different Departments, with no sense across government of the cumulative impact of their different decisions.

So, arguably as important for bus funding as the Department for Transport, is the Department of Housing, Communities and Local Government (which indirectly funds concessionary travel, as well as those services which operators won’t provide commercially). And then, in a separate box altogether, is over £1bn of Department for Education funding for schools transport.

All of which makes bus funding the transport equivalent of the Schleswig Holstein question – about which Palmerston said only three people understand it, one of whom was dead, the other mad and the other had forgotten all about it. Put bluntly, it’s a bad way to fund what is a very good thing.

The Treasury’s Spending Review is expected to run the rule over the Department for Transport’s main source of bus funding, the Bus Service Operators Grant, which provides a rebate on fuel duty. The mood music in Whitehall about protecting bus funding is far better than it was last time it was scrutinised in a Spending Review. But with the bus in sharp decline and punch drunk from previous funding cuts, now is the time for something more ambitious than tinkering and holding the line.

Jonathan Bray is Director at the Urban Transport Group.