Catastrophe: An Investigation Into the Origins of the Modern World (40 page)

In terms of Javanese history, the 535 eruption was a pivotal event, causing a cultural and political discontinuity in which ancient (west Javanese) civilization collapsed after flourishing for up to five centuries. But it was this very disaster—the destruction of west Javanese political/cultural predominance—that seems to have cleared the way for the rise of central Javanese political and cultural power in the seventh and eighth centuries
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While western Java remained a backwater for at least eight hundred years, the seventh century saw the emergence of several important new states in central Java. By 640 Chinese sources were remarking upon the power of a central Javanese kingdom called Holing. A second central Javanese kingdom, by the name of Mataram, also flourished and had taken over Holing by 720. By 900 this merged central Javanese polity had succeeded in uniting much of Java into a single state. Meanwhile, by the late eighth century in another part of central Java, another kingdom—ruled by the Shailendra dynasty—flourished and produced spectacular monumental architecture. One particularly notable temple, that of Borobodur, still covers half a square mile.

But then, in the tenth century
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., another volcanic catastrophe (Mount Merapi, c. 928) hit Java. This time it was the central portion of the island that was devastated. Borobodur was partially buried under volcanic ash (and fully reexposed only in our own century, a thousand years later), and the rulers of Mataram were forced to relocate their capital from central Java to the eastern periphery of their state—probably near the Surabaya area of eastern Java.

The Surabaya area quickly became the most powerful political center not only of Java, but of the Indonesian archipelago as a whole. Indeed, by the fourteenth and fifteenth centuries, the area had grown into the epicenter of a great empire, known—after its capital—as Mojopahit. Ruling over Java, Bali, eastern Sumatra, and southern Borneo, it was, in truth, a proto-Indonesia. But its distant early medieval origins were in central rather than eastern Java. And that original central Javanese civilization had probably been able to flourish only because ancient western Javanese power had been extinguished by the catastrophe of 535.

Thus modern Indonesia can be seen ultimately as the end product of a political process triggered by the disaster of the mid–sixth century.

I
t can be argued that most of the other countries that make up Southeast Asia also seem to owe their genesis to the eruption of 535. Throughout the region there was a marked geopolitical and cultural hiatus in the mid– to late sixth century, immediately following the catastrophe. Both the direct effects of the volcanic eruption and the consequent climatic problems must have hit agriculture and trade, and this in turn seems to have created economic and political imbalances between polities—imbalances that went on to produce fundamental changes across the region.

Proto-Thailand—the Kingdom of Dvaravati—came into existence in c.
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. 580. Proto-Cambodia (the Kingdom of Chenla) was born at virtually the same time, following the demise of the ancient Mekong Delta civilization of Oc Eo (Funan) sometime in the mid–sixth century. Proto-Malaya (the medieval Sultanate of Malacca) evolved out of a civilization in southern Sumatra that first emerged in the form of the Kingdom of Srivijaya in the middle of the seventh century, following the demise (probably as a result of the eruption) of the fierce prehistoric megalith-building warrior culture known to archaeologists as the Pasemah. And farther north, proto-Burma (the Kingdom of Sri-Ksetra) came to prominence around
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. 600 following the demise of its apparently more ancient rival, the Kingdom of Beikthano.

Thus, in its own way, Southeast Asia too fits the wider pattern of planetwide sixth-century destruction and subsequent political reformation, which helped destroy the ancient world and ushered in the proto-modern one.

R E C O N S T R U C T I N G
T H E  E R U P T I O N

R
econstructing the immediate sequence of events associated with a volcanic eruption that occurred fifteen hundred years ago is a daunting task—but not an impossible one. Using historical, tree-ring, ice-core, and other data, it is possible to compare the event and its climatic consequences with more recent eruptions of known size and effect.

Using the quasi-historical account in the Javanese
Book of Ancient
Kings,
it is possible, assuming the account to be at least part genuine, to gain an insight into specific aspects of the eruption itself. And using geological and volcanological knowledge of the area and records of more recent large eruptions, it is possible to reconstruct what probably happened.

Between 530 and 535, there would almost certainly have been a long series of earthquakes in what is now western Java, southern Sumatra, and the neighboring seas. These earthquakes and accompanying seismically triggered tidal waves may well have seriously disrupted life in the region. Typically, volcanic eruptions are preceded by increasingly frequent and violent tremors. Often the larger the eruption, the longer the seismic run-up to it will be.

In the case of the 530s catastrophe, the run-up to the eruption may even have included several earthquakes of level 6 on the Richter scale. Throughout the second half of 534, earthquakes would have struck the region at the rate of one or two per day. In the weeks immediately before the eruption, the rate would have accelerated to a peak of fifty quakes per hour in the final twenty-four hours, mainly in the range of 1 to 3 on the Richter scale.

Although it is a controversial proposal, it is geologically possible that Sumatra and Java were one island prior to the 535 supereruption—exactly as the Javanese
Book of Ancient Kings
describes.¹ The 535 eruption would therefore have burst forth from a volcanic mountain located on fairly low-lying ground where the shallow Sunda Straits between Java and Sumatra are today. For several years, a huge mass of molten magma would have been moving closer and closer to the surface—probably at the rate of up to thirty feet per month. This would have caused the land surface above to bulge upward into a low dome, increasing in height at up to three feet per year over perhaps a five-year period.

Then suddenly the pressure of the magma, two or three miles below the ground, would have proved too great; a crack would have opened up, and the first phase of the eruption would have started. A vast cloud of ash would have billowed forth, followed by a column of red-hot magma that would have shot out of the mountain like a fountain. A week or two later, as the magma came yet nearer to the surface, one of the earthquakes accompanying the eruption probably fractured the rock above the magma chamber, allowing the sea to rush into the wide tubes through which the magma was rising from the chamber to the surface. The second phase began with a vast explosive event that shot even larger quantities of molten magma into the air at up to 1,500 miles per hour, reaching heights of perhaps thirty miles. The sound from this explosion would have broken the eardrums of most humans and animals living within a fifteen-mile radius.

The shock wave from the explosion would have moved outward at 750–1,500 miles per hour, devastating everything in its path for up to twenty miles. Houses, bridges, temples, and every single tree would have been leveled like so many matchsticks. And within an estimated ten-mile radius there would also have been massive fire damage as the shock wave compressed the air, heating it to very high temperatures and causing combustible material to simply burst into flames.

Most of the molten magma fountain would have broken up into fragments ranging in size from less than a thousandth of an inch to a yard or more in diameter and would have partially solidified at an altitude of two or three miles. The larger fragments—along with car-sized chunks of the mountain itself—would have fallen back to earth within a radius of three to seven miles. The microfragments, however, would have been carried skyward by powerful convection currents.

As the second phase of the eruption continued, a vast mushroom cloud of ash and debris would have penetrated far into the stratosphere, reaching altitudes of up to thirty miles and carried aloft by extremely strong, high-temperature convection currents, moving at hurricane-force speeds.

In the center of the volcano, temperatures would have reached 1,650 degrees Fahrenheit, generating the heat that forced the ash cloud heavenward. As the mushroom cloud increasingly blotted out the light of the sun and day was turned into night, ash would have rained down on forests and fields alike up to a thousand miles away, and houses would have been shaken by the eruption at similar distances. The sea for dozens of miles around would have been covered with a six-foot-thick floating carpet of pumice, and ships at sea would have become terminally stranded in this volcanic quagmire.

Stupendous amounts of magma, vaporized seawater, and ultrafine hydrovolcanic ash (generated by magma-seawater interaction) would by now have been hurled into the sky, and a substantial percentage of it would have entered the upper part of the earth’s atmosphere, the stratosphere. As it spread sideways at high altitude, away from the immediate area of the eruption, the material cooled and the water-vapor component would have then condensed directly into vast clouds of tiny ice crystals. It is estimated that the entire eruption may have generated up to 25 cubic miles of ice crystals; spread out in a thin layer in the stratosphere, these would have caused sunlight diffraction and cooling over vast areas of the globe. Superfine hydrovolcanic ash and huge quantities of sulfur and carbon dioxide gas would have had similar effects. Unlike ordinary volcanic ash, which falls to earth within a few months, hydrovolcanic ash, high-altitude ice-crystal clouds, and sulfuric acid and carbon dioxide aerosols (minute drops) can stay in the stratosphere for years, forming a long-term barrier to normal sunlight and solar heat transmission.

Within hours after the start of the second phase of the eruption, part of the huge mushroom cloud above the volcano would have become too heavy with ash to stay aloft. This part would have collapsed back to the ground, spreading horizontally over land and sea in all directions away from the volcano in what is called a pyroclastic flow,² but thousands of times larger than similar flows that partly destroyed the island of Montserrat in the Caribbean in 1997–98.