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.

 
 
 
 

A helpful and informative guide to London, for the benefit of the New York Times editorial board

The sun rises over quaint old London town. Image: Getty.

It’s like with family members you hate: it’s fine for you to slag them off, but if anyone else has, you’re up in muted, backhanded arms about it.

Yesterday, the world’s number one London fan the New York Times tweeted a request for experiences of petty crime in the city. This was met by a deluge of predictably on-brand snark, like “Sometimes people scuff my leg and only apologise once”, and “Dicks who stand on the left-hand-side of tube escalators”. This served the dual purpose of uniting a divided London, and proving to the NYT that we are exactly the kind of chippy bastards who deserve to constantly lose their phones and wallets to petty crime.

By way of thanks for that brief endorphin rush, and in hopes of leading things in a more positive direction, I’d like to offer the Times this uplifting guide to London, by me, a Londoner.

I take my London like I take my coffee: on foot. If you are with someone special, or like me, like to reimagine your life in the format of Netflix dramady as you walk alone on Sundays, I can highly recommend the Thames Path as a place to start.

Kick things off next to Westminster, where we keep our national mace in the House of Commons. Useful though the mace might prove in instances of street theft, it is critical that it is never moved from the House. It acts as a power source for our elected representatives, who, if the mace is moved, become trapped in endless cycles of pointless and excruciatingly slow voting.

Cross Westminster Bridge to the Southbank, where in the manner of a spoiled 2018 Oliver Twist, you can beg for a hot chocolate or cup of chestnuts at the Christmas market for less that £8. Remember to hold your nose, the mutton vats are pungent. Doff your cap to the porridge vendor. (LOL, as if we make muttons in vats anymore. Box your own ears for your foolishness.) Then buy some hemp milk porridge, sprinkle with frankincense and myrrh, and throw it at the pigeons. There are thousands.

In the spring, head a little further south through Waterloo station. If you pass through the other side without getting ABBA stuck in your head, Napoleon’s ghost will appear to grant you three wishes.

Proceed to the Vaults, which is like the rabbit warrens in Watership Down, but for actors and comedians. No-one knows the correct way in, so expect to spend at least 45 minutes negotiating a series of increasingly neon graffiti tunnels. Regret not going to art school, and reward yourself upon your eventual entry with a drink at the bar. Browse the unintelligible show programme, and in no circumstances speak to any actors or comedians.

When you emerge from the Vaults three days later, turn back towards the river and head east. Enjoy the lights along the Thames while you pick at the spray paint stains on your coat. 


After about 20 minutes, you will reach the Tate Modern, which stands opposite St Paul’s Cathedral. Close to sunset, the sky, water, and cathedral might turn a warm peach colour. The Tate remains grey, coldly confident that for all its brutalist outline, it was still fantastically expensive to build. Feel grateful for that loose knit jumper you stole from the Vaults, and go inside.

Spend two minutes absorbing the largest and most accessible art, which is in the turbine hall, then a further hour in the museum shop, which is next to it. Buy three postcards featuring the upstairs art you skipped, and place them in your bag. They will never see the light of day again.

Head further east by way of Borough Market. Measure your strength of character by seeing how many free samples you are prepared to take from the stalls without buying anything. Leave disappointed. Continue east.

At Tower Bridge, pause and take 6,000 photos of the Tower of London and the view west towards parliament, so that people know. Your phone is snatched! Tut, resolve to take the embarrassment with you to your grave rather than shame Her Majesty's capital, and cross the river.

On the other side of the Bridge, you could opt to head north and slightly east to Shoreditch/Brick Lane/Whitechapel, where you can pay to enjoy walking tours describing how some pervert murdered innocent women over a century ago.

Don’t do that.

Instead, head west and north. through the City, until you reach Postman’s Park, which is a little north of St Paul’s, next to St Bartholomew's hospital. Go in, and find the wall at the far end. The wall is covered in plaques commemorating acts of extraordinary and selfless bravery by the city’s inhabitants. Read all of them and fail to hold back tears.

Then tweet about it.