|The Mount Tambora Caldera today (NASA Earth Observatory via Wikimedia Commons). Prior to the explosion, Mount Tambora was 14,000 ft high, afterwards it was 9354 ft. The crater is 4.3 miles wide and 2300 ft deep.|
An account of the eruption and the aftermath from Sophia Raffles' biography of her husband, Sir Stamford Raffles, is below, but is is worth pointing out the catastrophic size of the eruption first.
The explosion on 10th April measured 7 on the Volcanic Explosivity Index: a millenial-sized event, and 1 below the 'apocalyptic' level of a VEI8 explosion. It had 4 times the energy of the 1883 eruption of Krakatoa, equivalent to 800 megatons. 38 cubic miles of material was ejected by the explosion, eventually leaving a crater measuring 4.3 miles across and 2300 metres deep. The mountain itself reduced to two thirds of the original size. The explosion was heard up to 1600 miles away, and ash fell at least 810 miles away. Pitch darkness was observed up to 370 miles away for 2 days after the explosion, and a tsunami of up to 4 metres was experienced by many Indonesian islands.
Estimates of casualties vary, but at least 11,000 deaths were caused by the initial explosion, and it is thought 71,000 were caused in the longer term.
The eruption led to the 'Year Without a Summer'.
Mr. Raffles gives the following account of the eruption from the Tomboro Mountain, in the Island of Sambawa, which took place at this time (the 11th and 12th of April, 1815), one of the most violent and extraordinary of such explosions yet known.
"To preserve an authentic account of the violent and extraordinary eruption of the Tomboro Mountain on Sambawa, in April last, I required from the several Residents of districts on this Island a statement of the circumstances that occurred within their knowledge; and from their replies the following narrative is collected. It is, perhaps, incomplete until some further accounts are received of the immediate effects upon the mountain itself; but the progress is sufficiently known to render interesting a present account of the phenomenon, which exceeds any one of a similar description on record. The first explosions were heard on this Island in the evening of the 5th of April, they were noticed in every quarter, and continued at intervals until the following day. The noise was, in the first instance, almost universally attributed to distant cannon; so much so, that a detachment of troops were marched from Djocjocarta, in the expectation that a neighbouring post was attacked, and along the coast boats were in two instances dispatched in quest of a supposed ship in distress.
"On the following morning, however, a slight fall of ashes removed all doubt as to the cause of the sound; and it is worthy of remark, that as the eruption continued, the sound appeared to be so close, that in each district it seemed near at hand; it was attributed to an eruption from the Marapi, the Gunung Kloot or the Gunung Bromo.
"From the 6th, the sun became obscured; and it had every appearance of being enveloped in fog: the weather was sultry, and the atmosphere close and still: the sun seemed shorn of its rays, and the general stillness and pressure of the atmosphere foreboded an earthquake. This lasted several days, the explosions continued occasionally, but less violent, and less frequently than at first. Volcanic ashes also began to fall, but in small quantities; and so slightly as to be hardly perceptible in the western districts.
"This appearance of the atmosphere remained with little variation, until the 10th of April, and till then it does not appear that the volcano attracted much observation, or was considered of greater importance than those which have occasionally burst forth in Java. But on the evening of the 10th the eruptions were heard more loud, and more frequent from Cheribon eastward; the air became darkened by the quantity of falling ashes, and in several situations, particularly at Solo and Rembang, many said that they felt a tremulous motion of the earth. It is universally remarked in the more eastern districts, that the explosions were tremendous, continuing frequently during the 11th, and of such violence as to shake the houses perceptibly; an unusual thick darkness was remarked all the following night, and the greater part of the next day. At Solo, on the 12th, at four P. M., objects were not visible at 300 yards distance. At Gresie, and other districts more eastward, it was dark as night the greater part of the 12th of April, and this saturated state of the atmosphere lessened as the cloud of ashes passed along and discharged itself on its way. Thus the ashes, which were eight inches deep at Banyuwangi, were but two in depth at Sumanap, and still less in Gresie; and the sun does not seem to have been actually obscured in any district westward of Samarang.
"No description of mine, however, can so well express what happened, as the extracts from the reports at several places; the remarks there made are applicable also to all the other districts, only in a lesser degree, as the same became more distant from the cause of the phenomena.
EXTRACT OF A LETTER FROM GRESIE.
"' I woke on the morning of the 12th, after what seemed to be a very long night, and taking my watch to the lamp, found it to be half-past eight o'clock; I immediately went out, and found a cloud of ashes descending; at nine o'clock no day-light; the layer of ashes on the terrace before my door at the Kradenan measures one line in thickness; ten A. M. a faint glimmering of light can now be perceived over-head; half-past ten, can distinguish objects fifty yards distant; eleven, A. M. breakfasted by candle-light, the birds began to chirrup as at the approach of day; half-past eleven, can discover the situation of the sun through a thick cloud of ashes; one, P. M. found the layer of ashes one line and a half thick, and measured in several places with the same results; three, P. M. the ashes have increased one-eighth of a line more; five, P. M. it is now lighter, but still I can neither read nor write without candle. In travelling through the district on the 13th, the appearances were described with very little variation from my account; and I am universally told that no one remembers, nor does their tradition record, so tremendous an eruption. Some look upon it as typical of a change, of the re-establishment of the former government; others account for it in an easy way, by reference to the superstitious notions of their legendary tales, and say that the celebrated Nyai Loroh Kidul has been marrying one of her children, on which occasion she has been firing salutes from her supernatural artillery. They call the ashes the dregs of her ammunition.'
EXTRACT OF A LETTER FROM SUMANAP.
" ' On the evening of the 10th the explosions became very loud; one in particular shook the town, and they were excessively quick, resembling a heavy cannonade. Towards evening, next day, the atmosphere thickened so much, that by four o'clock it was necessary to light candles. At about seven, P.M., of the 11th, the tide being about ebb, a rush of water from the bay occasioned the river to rise four feet, and it subsided again in about four minutes; the bay was much agitated about this time, and was illuminated from a northerly direction. On the island of Sahotie, fire was seen distinctly at a short distance to the south-east. The uncommon darkness of this night did not break till ten and eleven, A. M., of the 12th, and it could hardly be called day-light all day. Volcanic ashes fell in abundance, and covered the earth about two inches thick, the trees also were loaded with them.'
EXTRACT OF A LETTER FROM BANYUWANGI.
" ' At ten, P. M. of the 1st of April, we heard a noise resembling a cannonade, which lasted, at intervals, till nine o'clock next day; it continued at times loud, at others resembling distant thunder; but on the night of the 10th, the explosions became truly tremendous, frequently shaking the earth and sea violently. Towards morning they again slackened, and continued to lessen gradually till the 14th, when they ceased altogether. On the morning of the 3rd of April, ashes began to fall like fine snow; and in the course of the day they were half-an-inch deep on the ground. From that time till the 11th the air was constantly impregnated with them to such a degree, that it was unpleasant to stir out of doors. On the morning of the 11th, the opposite shore of Bali was completely obscured in a dense cloud, which gradually approached the Java shore, and was dreary and terrific. By one, P.M., candles were necessary; by four, P.M., it was pitch-dark; and so it continued until two o'clock of the afternoon of the 12th, ashes continuing to fall abundantly: they were eight inches in depth at this time. After two o'clock it began to clear up; but the sun was not visible till the 14th, and during this time it was extremely cold. The ashes continued to fall, but less violently, and the greatest depth, on the 15th of April, was nine inches.
" ' All reports concur in stating, that so violent and extensive an eruption has not happened within the memory of the oldest inhabitants, nor within tradition. They speak of similar effects in a lesser degree, when an eruption took place from the volcano of Carang Assum, in Bali, about seven years ago; and it was at first supposed that this mountain was the seat of eruption in the present instance. The Balinese attributed the event to a recent dispute between the two Rajahs of Baliling, which terminated in the death of the younger Rajah, by order of his brother.
"' The haziness and heat of the atmosphere, and occasional fall of volcanic ashes, continued until the 14th, or, in some parts of the island, until the 17th of April: they were cleared away universally by a heavy fall of rain after which the atmosphere became clear and more cool; and it would seem that this seasonable relief prevented much injury to the crops, and removed an appearance of epidemic disease, which was beginning to prevail. This was especially the case at Batavia, where, for the two or three days preceding the rain, many persons were attacked with fever. As it was, however, no material injury was felt beyond the districts of Banyuwangi. The cultivators every where took the precaution to shake off the ashes from the growing paddy as they fell, and the timely rain removed an apprehension very generally entertained, that insects would have been generated by the long continuance of the ashes at the root of the plant. At Rembang, where the rain did not fall till the 17th, and the ashes had been considerable, the crops were somewhat injured. In Gresie the injury was less; but in Banyuwangi and the adjacent part of the island, on which the cloud of ashes spent its force, the injury was more extensive: 126 horses and eighty-six head of cattle also perished, chiefly from want of forage, during a month from the time of the eruption.
"' The local effects of this eruption have been ascertained by Lieutenant Owen Phillips, who proceeded to Sumbawa for this purpose, and was charged to distribute to the sufferers a supply of rice, dispatched by this government on hearing of the extreme distress to which the inhabitants of Sumbawa had been reduced.
"' The Noquedah of a Malay prow from Timor had reported that on the 11th of April, while at sea, far distant from Sumbawa, he was in utter darkness; that on his passing the Tomboro Mountain at a distance of five miles, the lower part of it was in flames, and the upper part covered with clouds: he went on shore for water, and found the ground covered with ashes to the depth of three feet, several large prows thrown on the land by a concussion of the sea, and many of the inhabitants dead from famine. On leaving Sumbawa, he experienced a strong current to the westward, and fell in with great quantities of cinders floating on the sea, through which he with difficulty forced his way: he was surrounded by them the whole of the night of the 12th, and says they formed a mass of two feet thick, and several miles in extent. This person states that the volcano of Carang Assam in Bali was in commotion at the same time; and it appears from the several reports, that a greater rumbling than usual was heard in the mountains in the Rembang district, as well as in the Gunning Gede in the Preanger Regencies; but after a strict inquiry, it does not appear that any simultaneous movement or connexion could be traced on this occasion along the chain of volcanic mountains running east and west in Java.'
" The Honourable Company's cruizer, Benares, was at this time at Macasar, and the following official report, received from the Commander of this vessel, confirms the circumstances already related.
" ' On the 5th of April, a firing of cannon was heard at Macasar, continuing at intervals all the afternoon, and apparently coming from the southward:—towards sunset the reports seemed to have approached much nearer, and sounded like heavy guns, with occasional slight reports between. Supposing it to be occasioned by pirates, a detachment of troops was embarked on board the Honorable Company's cruizer Benares, and sent in search of them, but after examining the neighbouring Islands, returned to Macasar on the 8th, without having found any cause of the alarm. During the night of the 11th, the firing was again heard, but much lower, and towards morning the reports were in quick succession, sometimes like three or four guns fired together, and so heavy that they shook the ship, as they did also the houses in Fort Rotterdam. Some of them seemed so near, that I sent people to the mast-head to look out for the flashes, and weighed at day-dawn, proceeding to the southward to ascertain the cause. The morning of the 12th was extremely dark and lowering, particularly to the southward, and S.W., the wind light, and from the eastward. At eight A.M. it was apparent that some extraordinary occurrence had taken place; the face of the heavens to the southward and westward had assumed a dark aspect, and it was much darker than before the sun rose; as it came nearer it assumed a dusky red appearance, and spread fast over every part of the heavens; by ten it was so dark that a ship could hardly be seen a mile distant; by eleven the whole of the heavens were obscured, except a small space near the horizon to the eastward, the quarter from which the wind came. The ashes now began to fall in showers, and the appearance was altogether truly awful and alarming. By noon the light that had remained in the eastern part of the horizon disappeared, and complete darkness covered the face of day. This continued so profound during the remainder of the day, that I never saw any thing to equal it in the darkest night; it was impossible to see your hand when held up close to your eyes. The ashes fell without intermission throughout the night, and were so light and subtile, that notwithstanding the precaution of spreading awnings fore and aft as much as possible, they pervaded every part of the ship.
" ' At six o'clock the next morning it continued as dark as ever, but began to clear about half-past seven; and about eight o'clock objects could be faintly discerned upon deck. From this time it began to get lighter very fast.
" ' The appearance of the ship when day-light returned was most singular ; every part being covered with the falling matter: it had the appearance of calcined pumicestone, nearly the colour of wood-ashes; it lay in heaps of a foot in depth in many parts of the deck, and several tons weight of it must have been thrown overboard; for though an impalpable powder or dust when it fell, it was, when compressed, of considerable weight; a pint measure of it weighed twelve ounces and three-quarters: it was perfectly tasteless, and did not affect the eyes with painful sensation, had a faint burnt smell, but nothing like sulphur: when mixed with water it formed a tenacious mud difficult to be washed off.
" ' By noon of the 12th, the sun made his appearance again, but very faintly, through the dusky atmosphere ; the air being still charged with ashes, which continued to fall lightly all day.
" 'From the 12th to the 15th the atmosphere remained thick and dusky, the rays of the sun scarce able to penetrate through it, with little or no wind the whole time.
" ' On the morning of the 13th left Macasar, and on the 18th made Sambawa. On approaching the coast, passed through great quantities of pumice-stone floating on the sea, which had at first strongly the appearance of shoals, so much so that I sent a boat to examine one, which, at the distance of less than a mile, I took for a dry sand-bank, upwards of three miles in length, with black rocks in several parts of it. It proved to be a complete mass of pumice-stone floating on the sea, some inches in depth, with great numbers of trees and logs, that appeared to be burnt and shivered as if by lightning. The boat had much difficulty in pulling through it; and until we reached the entrance of Bima Bay, the sea was literally covered with shoals of pumice and floating timber.
" ' On the 19th arrived in Bima Bay: in coming to an anchor grounded on the bank of Bima Town, shoaling suddenly from eight fathoms; hove off again as the tide was rising. The anchorage at Bima must have altered considerably, as where we grounded the Ternate cruizer lay at anchor in six fathoms a few months before. The shores of the bay had a most dreary appearance, being entirely covered with ashes.'
" From the account of the Resident of Bima, it appears that the eruption proceeded from the Tomboro Mountain, situated about forty miles to the westward of Bima. On the night of the 11th, he represents the explosions to have been most terrific, and compares them to the report of a heavy mortar close to his ear. The darkness commenced about seven in the morning, and continued twelve hours longer than it did at Macasar. The fall of ashes was so heavy as to break the Resident's house in many places, and render it uninhabitable, as well as many other houses in the town. The wind was still during the whole time, but the sea greatly agitated, its waves rolled in upon the shore, and filled the lower parts of the houses with water a foot deep. Every prow and boat was forced from the anchorage and driven on shore, and several large prows are now lying a considerable distance above high-water-mark.
" ' On the 22d, the Dispatch, country ship, arrived in the bay from Amboyna. It appears that this vessel had mistaken a bay to the westward, called Sampo or Sangin Bay, for Bima, and had gone into it: the Rajah of this place informed the officer that the whole of the country was entirely desolated, and the crops destroyed. The town of Sangin is situated about four or five leagues to the S. E. of the Tomboro Mountain. The officer found great difficulty in landing in the bay, a considerable distance from the shore being completely filled up with pumice-stones, ashes, and logs of timber: the houses appeared beaten down and covered with ashes.
" ' Understanding that messengers had been sent into the interior, I waited till the evening of the 22nd, and as they had not then returned, owing, as was supposed, to having found the country impassable, I left the bay at eleven o'clock that night, and the next day was off the Tomboro Mountain: in passing it at the distance of six miles the summit was not visible, being enveloped in clouds of smoke and ashes. The sides were smoking in several places, apparently from lava which had flown down them not being cooled; several streams had reached the sea; a very considerable one to the N.N.W. of the mountain, the course of which was plainly discernible, both from the black colour of the lava contrasted with the ashes on each side of it, and the smoke arising from every part of it. The Tomboro Mountain, in a direct line from Macasar, is about 217 nautical miles distance.'
" It has been ascertained that these eruptions of the Tomboro Mountain were heard through the whole chain of the Molucca Islands. The Honourable Company's cruizer Teignmouth was lying at anchor at Ternate on the 5th April; between six and eight P.M., several very distinct reports like heavy cannon were heard in the S.W. quarter, which was supposed to be a ship in the offing, in consequence of which the Resident sent a boat round the island to ascertain if it was so. The next morning, however, the boat returned without seeing any vessel in the offing; and the conclusion then drawn was that it might be occasioned by the bursting of some volcanic mountain in that quarter. Ternate Island 5° 0' N. 127° 30'E.
" The easterly monsoon, however, had at this time distinctly set in, and consequently the sounds would not be heard so loudly and distinctly in the Moluccas, as from the relative distance would otherwise have happened. They extended, in the opposite direction, to Fort Marlbro', and several parts of Sumatra, as appears from the following extract from thence:—
" ' It is an extraordinary fact, that precisely the same noise (taken by all who heard it to be a cannonade) occurred at several stations along this coast at the same time, viz., the morning of the 11th April: several gentlemen heard it in Marlbro', the people from the interior came down with accounts of it, and those from the higher Dusuns spoke of a kind of ash-dust which had covered the herbage and the leaves of the trees. Reports to the same effect (not mentioning any fall of ashes, however,) were received from Moco-moco, Laye, Salumah, Manna, Padang Guchee, Croce, and Semanka. From some of these stations the hill-people came down armed, to assist against attacks which they imagined might be made upon the head factories.'
" It has not appeared that any noise of this kind was heard at Padang, or much farther north than Moco-moco. I have since been told that the same noise was heard at Trumon in about 2' 40' N. lat., and at Ayer Bungi in about 0' 15' N. lat.. on or about the 11th April last.
" From Sumbawa to the port of Sumatra, where the sound was noticed, is about 970 geographical miles in a direct line; from Sumbawa to Ternate is a distance of 720 miles; and the existence of the S. E. monsoon at the time may account for the difference of distance to which the sound was heard in the westerly and easterly directions: the distance, also, to which the cloud of ashes was carried, so thickly as to produce utter darkness, is clearly pointed out to have been the island of Celebes, and the districts of Gresie on Java. The former is 217 nautical miles distant from the seat of the volcano—the latter in a direct line more than 300 geographical miles distant.
" I shall conclude this account with an extract of a letter from Lieutenant Owen Phillips, written from Bima on the 23rd ultimo. It has been mentioned in a former part, that on receiving intelligence of the extreme distress that had been occasioned by this extraordinary event, I dispatched a supply of rice to their relief, and Lieutenant Phillips was desired to proceed and adjust the delivery thereof, with instructions, at the same time, to ascertain, as nearly as possible, the local effects of the volcano. His report is as follows:—
" ' On my trip towards the western part of the island, I passed through nearly the whole of Dompo, and a considerable part of Bima. The extreme misery to which the inhabitants have been reduced is shocking to behold: there were still on the road-side the remains of several corpses, and the marks of where many others had been interred; the villages almost entirely deserted, and the houses fallen down, the surviving inhabitants having dispersed in search of food.
" ' In Dompo, the sole subsistence of the inhabitants for some time past has been the heads of the different species of palm, and the stalks of the papaya and plantain.
" ' Since the eruption, a violent diarrhoea has prevailed in Bima, Dompo, and Saugar, which has carried off a great number of people. It is supposed by the natives to have been caused by drinking water which has been impregnated with the ashes; and horses have also died, in great numbers, from a similar complaint.
" ' The Rajah of Saugar came to wait on me at Dompo on the 3rd inst. The sufferings of the people there appear, from his account, to be still greater than in Dompo. The famine has been so severe, that even one of his own daughters died from hunger. I presented him with three coyangs of rice in your name, for which he appeared to be truly grateful.
" ' As the Rajah was himself a spectator of the late eruption, the following account which he gave me, is, perhaps, more to be depended upon than any other I can possibly obtain:—
" ' About seven P. M., on the 10th of April, three distinct columns of flame burst forth, near the top of Tomboro Mountain, all of them apparently within the verge of the crater; and after ascending separately to a very great height, their tops united in the air in a troubled confused manner. In a short time the whole mountain next Saugar appeared like a body of liquid fire extending itself in every direction.
" ' The fire and columns of flame continued to rage with unabated fury, until the darkness caused by the quantity of falling matter obscured it at about eight P.M. Stones at this time fell very thick at Saugar; some of them as large as two fists, but generally not larger than walnuts. Between nine and ten P. M. ashes began to fall; and soon after a violent whirlwind ensued, which blew down nearly every house in the village of Saugar, carrying the tops and light parts along with it. In the part of Saugar adjoining Tomboro, its effects were much more violent, tearing up by the roots the largest trees, and carrying them into the air, together with men, houses, cattle, and whatever else came within its influence—(this will account for the immense number of floating trees seen at sea). The sea rose nearly twelve feet higher than it had ever been known to be before, and completely spoiled the only small spots of rice-lands in Saugar, sweeping away houses and every thing within its reach.
" ' The whirlwind lasted about an hour. No explosions were heard till the whirlwind had ceased, at about eleven A.M. From midnight till the evening of the 11th they continued without intermission; after that, their violence moderated, and they were only heard at intervals; but the explosions did not cease entirely until the 15th of July. The mountain still throws out immense volumes of smoke, and the natives are apprehensive of another eruption during the ensuing rainy season.
" ' Of the whole of the villages of Tomboro, Jempo, containing about forty inhabitants, is the only one remaining. In Precate, no vestige of a house is left. Twenty-six of the people who were at Sambawa at the time are the whole of the population who have escaped.
" ' From the most particular inquiries I have been able to make, there were certainly not fewer than 12,000 individuals in Tomboro and Precate at the time of the eruption.
" ' The trees and herbage of every description along the whole of the north and west sides of the Peninsula have been completely destroyed, with the exception of a high point of land near the spot where the village of Tomboro stood; on it a few trees still remain. In the night of the eruption, two men and two women, I am informed, escaped to this point, and were saved. I have sent in search of them, but have not yet been able to get hold of them; no person has yet been along the eastern side of the hill.
" ' A messenger who returned yesterday from Sambawa relates that the fall of ashes has been heavier at Sambawa than on this side the Gulf, and that an immense number of people have been starved: they are now parting with their horses and buffaloes for a half or quarter rupee's worth of rice or corn. The distress has, however, I trust, been alleviated by this time, as the brig, with sixty-three coyangs of rice, from Java, arrived there the day he was leaving it.'"
" Batavia, September 28, 1815."