At 12:25am on 15 April 1912 the Cunard liner Carpathia received a message to say that a ship, the Titanic, had struck an iceberg and required immediate assistance. Within a few minutes, the captain of the Carpathia, Arthur Rostron, had altered his course and began steaming towards the site of the stricken liner 58 miles away. By 4am, the Carpathia approached the spot of the collision and, in order to attract the attention of the survivors, the crew launched a spectacular array of rockets and Roman candles.

Over the course of the following four hours, lifeboat after lifeboat arrived at the Carpathia's side. The Titanic survivors were still enveloped by shock; Captain Rostron noted an atmosphere of stillness that accompanied them, many seemed to have been reduced to spectres by the experience. "Through it all that quietness reigned," said Rostron, "as though the disaster were so great that it silenced human emotion." The Captain insisted his ship steam around the site of the disaster in the hope of finding more survivors, but there was nothing to be seen on the surface of the water except for what witnesses described as a slight brownish discoloration, fragments of wood, a scattering of straw, the cork from macerated lifebelts and the occasional deck chair.

Survivors of the Titanic strained their eyes for the sight of other lifeboats in the hope that their loved ones might yet be saved. But none arrived. "All were looking for k a husband, son, brother or sweetheart, who never came," recalled Albert Caldwell, who had been travelling on the Titanic in second-class. Grief settled over the Carpathia as the realisation of the scale of the loss sank in – while 705 people had escaped, around 1,500 had died after the Titanic had hit an iceberg on its maiden voyage from Southampton to New York. The survivors had escaped with only the clothes they were wearing that night, and they wandered around the rescue ship in various states of dress. As one first-class passenger observed a few days later, "For four days the company lived together... in this strange assortment of undress costume, some in ball gowns, many in nightdresses and only a few fully clothed."

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With each mile the Carpathia sailed away from the scene, so the grief of its bereaved passengers intensified. Karl Behr, who had survived along with his sweetheart Helen Newsom, said, "Although the sinking of the Titanic was dreadful, to my mind the four days among the sufferers on the Carpathia was much worse and more difficult to forget."

On Thursday 18 April, the "ship of widows" sailed into New York Harbor. The city was enveloped in fog, but as the liner drew closer, passengers could dimly make out the brilliantly lit skyscrapers of Manhattan. In the distance they could hear the mournful tolling of bells. Survivor Edith Rosenbaum, who later changed her name to Russell, recalled that as she stepped off the ship and on to the pier she saw "thousands of people there" but heard not a sound, only "an intense silence, a silence of death... The quiet of the scene was broken by cries and sobs... All the time the bells kept tolling, and outside there was a cold drizzle of rain... The cannonade of flashes from photographers' lamps as we went into the street seemed a cruelly inappropriate thing."

It is at this point – when the Carpathia arrives in New York – that most accounts of the Titanic story end. Yet in many ways the Titanic is an ongoing narrative and today, as the 100th anniversary approaches, we remain as fascinated by the sinking and its aftermath as ever. Witnesses said that after the ship went down, the sea was as calm as a millpond. But for survivors such as Madeleine Astor, Jack Thayer and Dorothy Gibson, and many others, the echoes of that night continued to reverberate throughout their lives, the memories refusing to die away.

The Countess of Rothes, for example, recalled dining out with friends a year after the disaster when she "suddenly felt the awful felling of intense cold and horror" that she associated with her experience on the Titanic. She realised that the orchestra was playing The Tales of Hoffman, the last music she had heard at dinner on the night of 14 April 1912. Disassociation was a common complaint, a feeling of disembodiment and disconnection, while in the years that followed, a total of 10 survivors went on to commit suicide. Today, it's likely that many of them would be diagnosed with "survivor syndrome", a condition that was not defined until the 1960s and which is often marked by an overwhelming sense of guilt.

Writing in 1955, Marjorie Dutton – who travelled aboard the Titanic as an eight-year-old girl in second-class – described how her life seemed to be blighted or cursed. "My father was drowned taking our worldly wealth with him, as in those days people were not as bank-minded as they are now," she said. "Since that time I have been blessed with bad luck and often wonder if it will ever give me a break, but it just seems to be my lot... I think my name was published at the time as having been drowned."

Madeleine Astor

The widowed heiress lost a fortune – and then her dignity after her second, abusive husband sold their story

Even those survivors who occupied privileged positions did not escape the Titanic's shadow. Eighteen-year-old Madeleine Astor was travelling on the liner with her husband, John Jacob Astor (together, above), one of the richest men in the world. She had recently discovered she was pregnant and was returning home from her honeymoon in Egypt and Europe when she lost her husband in the disaster. As she disembarked the Carpathia in New York, one witness recalled: "I never saw a sadder face or one more beautiful, or anything braver."

Although Madeleine found herself a rich woman – she inherited the income from a $5m trust fund (equivalent to $114m today), an immediate payment of $100,000 and the right to live in a Fifth Avenue mansion – Astor's will carried a nasty sting in its tail. She would be eligible to benefit from the inheritance only if she remained unmarried for the rest of her life.

Madeleine – a bride, a widow, an heiress and a mother all in the course of a single year – played the part of the grieving widow to perfection, until she decided to forego the huge fortune and marry a man she had known since childhood. She went on to have two sons with William Dick, yet by 1932 Madeleine was bored with her all-too-ordinary existence. Thanks to her second husband's wealth, she was more than comfortably off; but she had told her doctor, who always travelled with her, that the Titanic had "ruined her nerves" and, as a result, she regarded herself as something of an "invalid".

In January 1932, Madeleine booked a first-class cabin on the Vulcania, where she met the handsome Italian prize fighter, Enzo Fiermonte. The boxer – whose name translated as "fiery mountain" – became infatuated by her wealth and, although both were already married and had children, the couple embarked on a messy, toxic relationship.

After their own marriage – which took place in November 1933 in a New York hospital after Madeleine broke her arm during a scuffle with Fiermonte – the couple caused an international scandal when they travelled to Italy. When he stepped on to Italian soil, the police seized Fiermonte's documents, as he had avoided compulsory military service while living in America, then the authorities impounded his passport. One lawyer told Madeleine that, as Italy did not recognise Fiermonte's divorce from his first wife, she "might face a sentence of from one to five years for participating in bigamy". Mussolini himself disapproved of Fiermonte's behaviour – "when he [Fiermonte] went to America he acted in a way Italy cannot approve", said a spokesman.

By the time the situation was smoothed out – with the help of a generous settlement for Fiermonte's first wife and son – the couple began to fight so violently that Madeleine's body was covered in bruises. According to court records, "Once he broke her wrist, and on another occasion he broke her ribs. She was frequently left bedfast by his attacks... Their final separation was late last year [1937] when Fiermonte beat her senseless." In May 1938, k Madeleine decided to make her husband a final severance settlement of $150,000 and file divorce papers on grounds of extreme cruelty.

Then, a year later, she experienced a betrayal worse than any barbed insult or petty infidelity: Fiermonte sold the story of their marriage to the vulgar True Story magazine. Claiming to stand as "one of the most startling and illuminating commentaries on life among the idle rich ever written", the serialisation over the course of three months devastated Madeleine. Her reputation ruined, she felt depressed, almost suicidal. And after hearing of the death of her mother, in August 1939, she became increasingly dependent on prescription drugs. On 27 March 1940, she died at the age of 47. While the official cause of death was heart failure, it was rumoured that she had taken an overdose of sleeping pills. Fiermonte – who went on to fulfill his dream of becoming an actor – later said of his former wife that, "She carried her doubts with her always, like her pearls."

Jack Thayer

After losing his father to the Atlantic, the banker lost his son to the Pacific

In many respects, Jack Thayer seemingly personified the word "survivor". In the Titanic's final moments, the 17-year-old, who'd been travelling in first-class with his parents, waited until the ship had almost submerged before he jumped from a rail into the sea. "The shock of the water took the breath out of my lungs," he recalled. "Down and down I went, spinning in all directions." And there was something almost miraculous about his survival: "I finally came up with lungs bursting, but not having taken any water."

Thayer had lost his father in the disaster, but bore his grief with dignity and honour, and after returning to America with his mother, Marian, another Titanic survivor, he attempted to resume his life as though nothing had happened. In 1913, he began to court Lois Buchanan Cassatt, the great-great-niece of James Buchanan, the former president of the United States. By 1917, the couple had announced their engagement and, on 15 December of that year, they married in Philadelphia. The following September, John, the first of their six children was born (one died in infancy from Spanish flu). Yet Jack was not there to see the birth of his first and favourite son, as he was fighting in France. On the Meuse-Argonne front, he would have witnessed death on a mass scale. "That must have been a horrible experience for him, but when he returned home I don't think he talked much about it," says Thayer's daughter, Julie Vehr. "Like he never talked about the Titanic. In those days, a man did not talk about his feelings. In fact, nobody really talked about emotions at all. It just wasn't done."

After a career in banking, in 1937 Jack accepted a job as treasurer of the University of Pennsylvania; and then, in 1944, he was promoted to the position of financial vice-president. By all accounts he led a busy, active, seemingly happy and fulfilled life. "One year, when the Schuylkill River in Philadelphia was frozen over, he took us down to skate," says Julie. "I remember being quite scared, in case the ice would give way and I would fall in and get trapped beneath it, but he said, 'Don't worry, I've got my rope with me.' It was a kind of pole with a rope wrapped around it that he said he could use to pull us out of the water if we fell in. Looking back, it is curious that he should want to go on frozen water after what he had been through with the Titanic. Of course, at the time I thought nothing of this, as he never, ever mentioned the disaster. He was not afraid of water, and loved to swim, but he never sailed and would never go on an ocean liner." He may not have verbalised his recollections of the sinking and its aftermath, "but he must have thought about that night a great deal," says his daughter, Pauline Maguire. "I never knew anything about the Titanic as a child, as it was never mentioned in the family."

As Thayer's children began to approach the age he had been when he took that fateful voyage, Jack began to think about how to deal with his memories of the Titanic – images, conversations, emotions, fears he had kept to himself for nearly 30 years. "I think he wanted us children to know what had happened that night and so he wrote an account of the sinking just for the family," says Vehr. The disaster, he wrote, "not only made the world rub its eyes and awake, but woke it with a start, keeping it moving at a rapidly accelerating pace ever since, with less and less peace, satisfaction, and happiness". In many ways, the event became symbolic of the modern age itself: an overture that served as a prelude to a century of disquiet and disorder. "Today the individual has to be contented with rapidity of motion, nervous emotion, and economic insecurity," wrote Thayer. "To my mind the world of today awoke April 15th, 1912." As he wrote those words, in 1940, little did he realise the extent of the personal horrors he would still have to endure.

After writing his account of the sinking, Jack tried to contain his recollections of the Titanic. Yet a messy spillage of fragmented memories began to emerge from the depths. Could the act of remembrance – and its subsequent expression in words – have triggered this new wave of "nervous emotion"? Had the articulation of past events, an act he had assumed would result in the calming of the sea of memory, made the situation worse? Whatever the reason, Thayer – respectable, honourable, extrovert, fun-loving, seemingly well-rounded as he was – began to experience an anxiousness that would not leave him, and the strength he had shown to the world over the past 30 or so years began to slip away. Everything seemed to be connected to that night; whatever he did, the Titanic was always there at the edge of his consciousness, taunting him. In October 1943, he learnt the news that his 22-year-old son, Second Lieutenant Edward Cassatt, a co-pilot of an American bomber, had been killed in action in the Pacific. The thought of his son's plane plunging into water forced the sinking of the Titanic to the front of his consciousness again. "Edward was lost over one of the islands in the Pacific," says Maguire, "and I think it must have brought back the memory of the water."

Then, just six months later, his mother, who had been ill with a heart condition for a year, died, aged 72. The double loss was hard enough to bear, but the date – 14 April 1944 – was the strange thing, as Marian had died all but on the 32nd anniversary of the Titanic disaster. "He started to suffer from depression," says Vehr. "It was a result of everything that had happened to him over the years – the Titanic, losing his son and then his mother. Eventually, it seems he suffered a nervous breakdown. My mother sought medical help for him, but one day he slipped away from watchful eyes." k

On the morning of 18 September 1945, 50-year-old Jack Thayer left his office at the University of Pennsylvania and drove through the streets of Philadelphia. At the city's trolley loop, near 48th Street and Parkside Avenue, he slowed down, pulled over, then proceeded to slash his wrists and throat.

"Maybe my mother had had some warnings, but as children it was the last thing we expected," says Vehr. "I was 17 when he died, and it came as a complete shock. It was terribly sad." "One of my sisters was embarrassed to go to school afterwards," says Maguire, "but I thought we shouldn't be embarrassed, as you would need so much courage to do it. At the time, he didn't do it because he was brave, however; he did it because he was desperate."

Dorothy Gibson

The actress escaped a messy divorce in the States by fleeing to Europe – and ended up in a concentration camp

For a cynical few, the Titanic was nothing more than an experience to be mined, an opportunity to turn dolour into dollars. Within moments of stepping off the Carpathia, silent-screen star Dorothy Gibson, who survived the Titanic with her mother Pauline, met with her lover – the wealthy, but married film pioneer Jules Brulatour – and hatched a plan to make a film of the disaster starring herself.

Shooting began almost immediately at the Fort Lee studio in New Jersey and on location on board a derelict freighter in New York Harbor. Wearing the same outfit she had worn the night the ship went down – a white silk evening dress, a sweater, overcoat and black pumps – the verisimilitude of the experience was overwhelming. "She had practically lost her reason," wrote one witness who attended the shoot for the film, Saved from the Titanic, in effect the world's first exploitation movie. A reporter also present described how "the cameramen advanced upon her alone on the deck of this supposedly doomed ship", and how they "witnessed a tragic bit of acting that stirred even their hearts, accustomed as they were to weekly scenes of the kind".

Yet this wasn't so much acting, in its conventional form at least, as replaying. Gibson drew on her memory and shaped it into a reconstruction, transforming herself in the process, imagining a substitute self that was in many ways more heroic than the real one. The true reason she broke down on set was the momentary inability to reconcile her lived behaviour with the fantasy she was creating for the cameras. Perhaps she did feel some guilt, a sense of shame that she had survived. She had not only listened to the screams of 1,500 or so fellow passengers as they struggled in the freezing water, but, while in the lifeboat, she had colluded in the refusal to go back to rescue the dying. She was indeed "Saved from the Titanic", but, in some ways, she was also damned.

After living as a mistress for so long, by the time Gibson walked down the aisle with Brulatour, in July 1917, she felt married life to be nothing but an awful anticlimax. Within a matter of months, both started to seek new partners. In August 1919, Dorothy appealed in court for alimony of $48,000, a request that was reduced to $10,000. The judge was so appalled by the behaviour of the pair that he went so far as to make a public statement, reprimanding them for their "unprincipled conduct". After Brulatour married the actress Hope Hampton in 1923, Dorothy decided to leave America for Europe. "I had a great deal of unhappiness and much less money," she later said. "Mr Brulatour had married again, and we still had many of the same friends... Therefore I went to Paris to live with my mother."

Gibson's new life should have been one of pure hedonism and, at first, she enjoyed her bohemian existence. In 1934, she said, "I fear it cannot go on like this always. I have had my dream life, and am sure that someday a dark cloud will come and wash it all away." Little did she realise that this "dark cloud" was nothing less than the Second World War. Displaying characteristically poor judgement, she and her mother, believing that Hitler would win the war, aligned themselves with Fascist elements. Gibson fell in love with Antonio Ramos, the press attaché for the Spanish Embassy in Paris. Her mother, for her part, idolised Mussolini, and chose to base herself in Florence. As Dorothy was driving from Paris to Florence, in order to bring her mother back to France, Germany invaded Holland and Belgium. Unhindered travel suddenly proved more difficult, yet it would still have been possible for the two women to return to America. The reason they didn't? Certainly, their experience on the Titanic was a factor. "I must say I never wanted to make the ocean trip to America at this time," Gibson later said in an affidavit, "as my mother and I were most timid on the ocean – we had been in a shipwreck – but I also never wanted to stay in Italy."

In the spring of 1944, while still in Florence with her mother, Gibson was informed by the Italian state police that she would be taken to the German-controlled Fossoli internment centre. She tried to escape, travelling on foot towards the Swiss border, but on 16 April she was arrested in Cannobio and taken to a Nazi concentration camp. After being moved around various camps, she was imprisoned at San Vittore, which she described as a "living death". It's likely Gibson would have died there had it not been for the machinations of a double agent, Ugo Luca Osteria, as she – together with two men – was smuggled out of the concentration camp under the pretence of being a Nazi sympathiser and spy. For Gibson, this was perhaps one role too many: although the plan worked, and she managed to cross into Switzerland, the experience left her exhausted. After being interrogated in Zurich, she was judged too stupid to have been a genuine spy. In the words of the vice-consul of the American Consulate General, she "hardly seems bright enough to be useful in such capacity".

After the war ended in 1945, Gibson, who suffered from extremely high blood pressure, returned to Paris and enjoyed a few months at the Ritz, where she died in February 1946, probably from a heart attack. No cause of death was cited on her death certificate, but it's tempting to fill the empty space with the word "Survivor". If she had not travelled on the Titanic, it's unlikely she would ever have made the transition from Brulatour's mistress to wife; neither would she have become so infamous that she felt the need to flee the US for Europe. The guilt that came with surviving the Titanic, and the subsequent exploitation of its memory, lay heavy on her heart until finally it could stand it no longer.

'Shadow of the Titanic: The Extraordinary Stories of Those Who Survived' by Andrew Wilson is published by Simon & Schuster, priced £19.99