‘Where Australia Collides with Asia’ – The Darwin Earthquake

On June 24, Darwin was jolted by a magnitude 7.3 earthquake, prompting offices in the CBD to be evacuated. The epicentre was some 700 kilometres away to the north in the Banda Sea of Indonesia. But despite the distance, the quake rocked Darwin hard, because it occurred within the same tectonic plate, rather than at the boundary between two neighbouring plates.


Where the Australian Plate collides with Asia some of it has slid (subducted) under the volcanoes of Eastern Indonesia, and is descending into the mantle. This process is driven by buoyancy (the tendency of material to sink or float). Continental crust is more buoyant, and thus resists sinking into the mantle. Ocean crust, meanwhile, is denser and has more of a tendency to sink. As the Australian Plate (which includes New Guinea) travels northward, the front edge is high-density ocean crust, and the part following behind it is lower-density continental crust. The map below shows the plate boundaries and relevant movement within our region.


Plate Boundaries and relevent movement

Where one part of a plate subducts easily and starts to sink and the other wants to float and refuses to subduct, a tear can develop, and this is what is believed is happening north of Darwin. The northern edge of the Australian Plate used to be made up of ocean crust that is now completely subducted. The buoyant Australian continent is refusing to subduct, and as a result the ocean crust is tearing off as it sinks into the mantle.

This NASA image from satellite telemetry maps displays height above and depth below sea level. It shows the edge of the Asian continent at the Wallace Line  and how the Australian continent is impacting on the Indonesian island arc system along the edge of the Banda Sea.

Wallace Line 3

A useful analogy to visualise this is tearing a piece of cheese – the kind of pre-sliced, soft cheese that you put on your sandwiches. The picture below shows a piece of cheese that is bent around a cylinder (representing the descent of the plate into the mantle), and is torn along one edge.

darwin earthquake

The official earthquake record from the US Geological Survey indicates that this earthquake consisted of a combination of lateral displacement and vertical extension (lengthening), which is consistent with the cheese analogy. The vertical extension is caused by the stretching of the crust while lateral displacement, known as strike slip, probably accommodates the eastward movement required by the continuing attachment of the slab east of the earthquake. Earthquakes such as this occur within the Australian plate, and the seismic waves travel through the cold, strong Australian plate quite efficiently. This means that it did not lose much of its energy before reaching Darwin.

This blog is based on an article in ‘The Conversation’ by Brendan Duffy a Lecturer in Applied Geoscience at the University of Melbourne and Mark Quigley an Associate Professor at the University of Melbourne.

Cover 8




Posted in Uncategorized | Tagged , , , | 6 Comments

Dragon’s Paradise Lost – Varanus komodoensis

Komodo Island. 2png


I have always been curious whether the Komodo Dragon found on the island of Komodo, located between Sumbawa and Flores, is a large goanna (lizard) caused by island gigantisism or the last of the Australian megafauna, which we know from fossil evidence used to range over Australia up to 50,000 years ago . Well here is the answer:

Megalania is an extinct giant goanna or monitor lizard that was part of a megafaunal assemblage that inhabited southern Australia during the Pliestocene. The youngest fossil remains date to around 50,000 years ago. It is thought that the first aboriginal settlers of Australia would have encountered them and been a factor in their extinction.


Megalania skeletal reconstruction from the Melbourne Museum

Giant varanids were once a ubiquitous part of  Australasian faunas during the Neogene. Extinction played a pivotal role in the reduction of their ranges and diversity throughout the late Quaternary, leaving only Varanus komodoensis in Indonesia as an isolated long-term survivor. The events over the last two millennia now threaten its future survival.


Varanus komodoensis

Dragon’s Paradise Lost: Palaeobiogeography, Evolution and Extinction of the Largest-Ever Terrestrial Lizards (Varanidae)

The conclusion from the above paper published in the Public Library of Science reads:

We conclude that Varanus komodoensis is the last of a clade of giant varanids that was once a ubiquitous part of Australasia, distributed from Australia across Wallacea, as far as Java. There is now only a relict population on Flores and a few small adjacent islands. Komodo dragon distribution has also retracted significantly on Flores itself; being present at Liang Bua in the uplands of West Flores until ∼2 ka, but now only occurring in isolated habitats along the northern and western coastal lowlands. The retraction is likely due to habitat loss and persecution by modern humans over the last few millennia and emphasizes the continuing threat of extinction to this, the last of the giant varanids.

Komodo Claw

The armoured body and deadly claws of Varanus komodoensis

The Komodo dragon’s diet is wide-ranging and includes other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo.The Komodo dragon will attack children and there have been deaths in the few villages on the island but it rarely attacks adults.

The most well-known adult victim is Baron Von Reding Biberegg, a Swiss man who disappeared on Komodo Island in 1974. Walking inland with a group to observe the dragons, the Baron was breathing heavily and stopping frequently. He told the other members to go on ahead while he sat down to rest. He may have fallen asleep or suffered a medical condition for when his party returned all that remained was his hat, his camera and a bloody shoe.

DSCN3225 - Copy

Who is this idiot?  What could I have been thinking?

My thanks to Oscar Croshaw for directing me to the paper on Dragon’s Paradise Lost

    To read more about Komodo Island and the Komodo Dragon find  the book                    Archipelago: A Journey Across Indonesia, by Ian Burnet





Posted in Uncategorized | Tagged , , , , | 2 Comments

In Search of the Wallace hut on the island of Waigio

In June and July 1860, Alfred Russel Wallace sailed north from the island of Ceram in Maluku to the island of Mysool and then to the south coast of the island of Waigio near Papua in search of Birds of Paradise.

Wallace Voyages

Wallace’s Voyages around the Indonesian Archipelago (Ian Burnet)

From Alfred Russel Wallace’s The Malay Archipelago:

‘Leaving the village the next morning (July 1st) with a light wind, it took us all day to reach the entrance to the channel, which resembled a small river, and was concealed by a projecting point, so that it was no wonder that we did not discover it amid the dense forest vegetation which everywhere covers these islands to the water’s edge’.

dsc06363 - copy

Searching for the ‘Wallace Hut’ on Waigio (Ian Burnet)

From Alfred Russel Wallace’s book The Malay Archipelago:

‘This part of Waigiou appears to consist of almost entirely of raised coral. The shores were a range of low limestone cliffs, worn out by water, so that the upper parts generally overhung. At distant intervals were little coves and openings, where small streams came from the interior; and in one of these we landed, pulling our boat up on a patch of white sandy beach. Immediately above was a large newly made plantation of yams and plantains, and a small hut, which the chief said we might have use of if it would do for me’.

wallaces hut

A sketch of Wallace working under his ‘dwarfs house’ from his book The Malay Archipelago

He spent from July to September 1860 in his hut and this is its description from The Malay Archipelago:

‘It was quite a dwarf’s house, just eight feet square, raised on posts so that the floor was four and half feet above the ground, and the highest part of the ridge only five feet above the floor. As I am six feet and an inch in my stockings, I looked at this with some dismay; but finding that the other houses were much further from water, were dreadfully dirty, and were crowded with people, I at once accepted the little one, and determined to make the best of it.

In the lower part I fixed up a small table, arranged my boxes, put up hanging shelves, laid a mat on the groundwith my wicker chair upon it, hung up another mat on the windward side, and then found that, by bending double and carefully creeping in, I could sit on my cahir with my head just clear of the ceiling. Here I lived pretty comfortably for six weeks, taking all my meals and doing all my work at my little table, to and from which I had to creep in a semi-horizontal position a dozen times a day; and after a few severe knocks on the head by suddenly rising from my chair, learned to accomodate myself to circumstances’.


The male Red Bird of Paradise performing its mating dance on Waigio

‘I began to think that we would not get this magnificent species. At length the fruit ripened on the fig tree close to my house and many birds came to feed on it; and one morning as I was taking my coffee a male paradise bird waa seen to settle on its top … the head back and shoulders are clothed with a rich yellow, the deep metal green colour of the throat extends further over the head, and the feathers are elongated on the forehead into two little erectile crests. The side plumes are shorter, but are of a rich red colour, terminating in delicate white points, and the middle tail feathers  are represented by two long rigid glossy ribbands, which are black, thin, semi-cylindrical and droop gracefully into a spiral curve’.

wallaces hut 2

The Wallace Hut as rebuilt by Seatrek Sailing Adventure and Flora and Fauna International (Jeffrey Mellefont)

This plaque at the Wallace Hut honours the memory of both Alfred Russel Wallace and of Tony Witten of Flora and Fauna International, who was instrumental in having it built.



Looking somewhat worse for wear (the hut that is) during our 2018 visit with Seatrek Sailing Adventures   (Richard Orr)

Find out more about the Alfred Russel Wallace, the Wallace Line and the region of Wallacea in Ian Burnet’s latest book – Where Australia Collides with Asia.

Where Australia Collides with Asia - IHS poster 2






Posted in Uncategorized | Tagged , , , , , , , , | 5 Comments

Banda Island and the Banda Sea marine gardens

The Banda volcano (Gunung Api or Fire Mountain) is a perfectly conical mountain that rises 656 meters above sea level, and is about 3 kilometres wide. The nutmeg island of Banda has been a key location in the spice trade and historical eruptions have been recorded there since the late 1500s. These have been relatively low-level, although there have been the occasional larger eruptions with the lava flow reaching the coast as can be seen on this photograph.

Flying over Gunung Api

Gunung Api showing the most recent lava flow from 1988

After 97 years of dormancy a violent eruption shook the Banda islands in May 1988 as Gunung Api exploded. A column of ash billowed 3 kilometres into the air and tremors were felt every few minutes. On the day of the eruption, people began moving to further islands, eventually about 10,000 people of the 16,000 population living in the Banda islands were evacuated during the eruption, which finally ended in August 1988. The photograph below shows the Dutch church in Banda with the erupting Gunung Api and the huge ash column in the background.


Gunung Api erupting

The Dutch Church in Banda with Gunung Api erupting in 1988


13 - Copy

The Banda Sea marine gardens

Marine scientists have monitored the coral colonization on 3 locations adjacent to the lava flow and in just 5 short years, the hardened andesitic flow has supported over 120 species of coral. A larger diversity and abundance than the adjacent reef not affected by lava.

tLerxLGJ - Copy

The Banda Sea marine gardens


Now, 30 years later, coral growth around the lava flows from Gunung Api not only matches, but exceeds the development that normally takes coral formations over 70 years to achieve, making it the most rapid growing coral in the world. The reason is probably the heat or mineralization generated by the lava flow.

26 - Copy

The Banda Sea marine gardens


Thanks to Carleen Devine for permission to use her excellent underwater photographs.


Posted in Uncategorized | Tagged , , , , | 1 Comment

Alfred Russel Wallace’s publication of ‘The Malay Archipelago’

This week we celebrate the 150 year anniversary of the publication of Alfred Russel Wallace’s book, The Malay Archipelago. This wonderful book is an account of the eight years he spent in British Malaya and the Dutch East Indies collecting natural history specimens, including his discovery of the biogeographic boundary between Asia and Australia which came to be called ‘The Wallace Line’, his descriptions of the region between Asia and Australia which came to be known as ‘Wallacea’, and the recognition from his studies of the fauna that Australia had collided with Asia.

The Malay Archipelago is undoubtedly the classic work on the flora, fauna and peoples of the area which is now called Malaysia and Indonesia. Based largely on four field journals which Wallace kept during the eight years he spent there between 1854 and 1862, it ranks as the greatest travel book on the region and for its analysis of the geographic distribution of animals, it is one of the most important natural history books of the nineteenth century.

Where Australia Collides with Asia - IHS poster 2

The main purpose of Wallace’s travels, as he states in the preface to his book, was to obtain natural history specimens for his private collection and to sell duplicates to museums and amateur naturalists through his agent in London. Altogether he collected an astonishing 125,660 specimens of natural history, mainly beetles, butterflies and birds from across the archipelago.

The Malay Archipelago was published in London on 9 March 1869 in two volumes of 1500 copies and it quickly sold out. A second edition of 750 copies came out in October that year and edition after edition followed.  A German translation came out in 1869 and a Dutch translation in 1870 and it is believed that the book has never been out of print.

062 The_Malay_Archipelago_Darwins copy

This is Charles Darwin’s original copy which was donated to the British Museum after his death

The Malay Archipelago was dedicated to Charles Darwin and he must have received an advance copy because he wrote to Wallace on 5 March 1869. ‘ I was delighted at receiving your book this morning. The whole appearance and the illustrations with which it is so profusely ornamented are quite beautiful … As for the dedication, putting quite aside how far I deserve what you say, it seems to me decidedly the best expressed which I have ever met.

Darwin dedication

The dedication to Charles Darwin from the frontispiece of The Malay Archipelago

Wallace begins The Malay Archipelago with this evocative description of the region:

If we look at a globe or a map of the eastern hemisphere we shall percieve between Asia and Australia a number of large and small islands, forming a connected group distinct from those great masses of land, and having little connection with either of them. Situated upon the equator, and bathed with the tepid water of the great tropical oceans, this region enjoys a climate more uniformly hot and moist than almost any other part of the globe, and teems with natural productions which are elsewhere unknown. The richest of fruits and the most precious of spices are here indigenous. It produces the the giant flowers of the Rafflesia, the great green-winged Ornithoptera (princes among the butterfly tribes), the man-like orang-utan, and the gorgeous birds of paradise. It is inhabited by a peculiar and interesting race of mankind – the Malay, found nowhere beyond the limits of this insular tract, which has hence been named the Malay Archipelago.

What is interesting is that nowhere in The Malay Archipelago does Wallace mention his famous ‘Letter from Ternate’ or his essay ‘On the Tendency of Species to Depart Indefinitely from the Original Type’ which he wrote in three days and sent to Charles Darwin from Ternate in March 1858. Stating that he “hoped the idea was as new to Darwin as it was to himself and that he believed it would supply the missing factor to explain the origin of species”. Of course the idea was not new to Darwin, although he had never published his theory,  and it was Wallace’s letter which precipitated the joint presentation to the Linnean Society in July 1858, while Wallace was still in the Dutch East Indies, of his and Darwin’s common theory on the Origin of Species.

Wallace Darwin Medal

The two sides of the Darwin-Wallace Gold Medal

The 50th Anniversary of this momentous event was celebrated in 1908 when Alfred Russel Wallace was presented the Darwin-Wallace Gold Medal. The President of the Linnean Society, in welcoming the delegates and guests on this occasion, said:—

“We are met together today to celebrate what is without doubt the greatest event in the history of our Society since its foundation. Nor is it easy to conceive the possibility in the future of any second revolution of Biological thought so momentous as that which was started 50 years ago by the reading of the joint papers of Mr. Darwin and Dr. Wallace, ‘On the Tendency of Species to form Varieties’ and on the ‘Perpetuation of Varieties and Species by Natural Means of Selection’ …

Darwin and Wallace not only freed us from the dogma of Special Creation, a dogma which we now find it difficult to conceive of as once seriously held —they afforded a natural explanation of the marvellous indications of Design which had been the great strength of the old doctrine…

Dr. Alfred Russel Wallace, We rejoice that we are so happy as to have with us today the survivor of the two great naturalists whose crowning work we are here to commemorate. Your brilliant work, in Natural History and Geography, and as one of the founders of the Theory of Evolution by Natural Selection, is universally honoured and has often received public recognition, as in the awards of the Darwin and Royal Medals of the Royal Society, and our own medal in 1892. Today in asking you to accept the first Darwin-Wallace medal, we are offering you of your own, for it is you, equally with your great colleague, who created the occasion which we celebrate today.”









Posted in Uncategorized | Tagged , , , , , | Leave a comment

Swimming with Whale Sharks in Papua

The map below shows our October 2018 voyage with Coral Expeditions from Biak to Darwin. There is no doubt that the highlight  of the voyage was swimming with whale sharks in Cenderawasih Bay in Papua.

October 2018 facebook


The whale shark is the largest non-cetacean animal in the world with an average length of 10 metres and weighing 9 tonnes. They are actually sharks although they have tiny teeth because they are filter feeders like whales, living on plankton and small squid or fish. The whale shark inhabits warm tropical or temperate waters, is pelagic and lives in the open sea, but seasonal feeding aggregations occur at many sites around the world including Cenderawasih Bay shown in the centre of this map of Indonesian Papua.

Cendrawasih Bay

We fly from Darwin to Biak where we join the Coral Discoverer and sail south into Cenderawashih Bay (Bird of Paradise Bay) looking for the Bagans (floating fish traps) to which the whale sharks are attracted by an expansive seafood menu.



We leave the Coral Discoverer on the smaller Xplorer vessel and approach the Bagan with some of our group already in the water.


A whaleshark feeding next to the Bagan net. It feeds by sucking in large volumes of water and then expelling it through its gills



Is that me on the right? Look for another whaleshark in the background left. It was a fantastic morning and we had nine whalesharks around us including an infant.

WS3Oh My!  What a big mouth you have. Think of Jonah and the whale. The small fish attached to the bottom of the whale sharks live off whatever they clean off their skin.


Thank you to my fellow Coral Expedition explorers for their underwater photographs


To complete a wonderful day we went ashore at Kwatisore to meet the villagers, to be entertained with some traditional singing and dancing, and to browse their market


DSCN2417 - Copy



The next voyage to Papua, Cenderawasih Bay  and the Spice Islands with Coral Expeditions will be in December 2019 and January 2020 aboard the Coral Adventurer. Please go to their website for more details.




Posted in Uncategorized | Tagged , , , , , | 3 Comments

Ian Burnet talking at ‘Better Read than Dead’


Posted in Uncategorized | Tagged , , , , | 1 Comment