Homes destroyed. Crops ruined. Livelihoods snuffed out. This week witnessed another trail of devastation caused by catastrophes in Southeast Asia, scenes that are depressingly familiar in the world’s most disaster-prone region.

At least 16 people died and more than 500 hikers needed rescuing from the slopes of Indonesia’s Mount Rinjani after an earthquake struck on Sunday night – while more than 5,000 local residents on the island of Lombok were effectively left homeless.

Meanwhile, flash flooding deprived entire communities of food, security and shelter in south-eastern Laos, and across the border into Cambodia, following the collapse of a hydroelectric dam. At least 20 died and hundreds were reported missing and 6,600 people were left stranded or seeking refuge in makeshift refugee camps and evacuation centres.

Less well reported are the human tragedies that tend to follow these catastrophes. Not the immediate fatalities, injuries or loss of homes and incomes caused by the disasters themselves – though they are frequently severe – but rather crimes and violence, particularly against women and children, in the aftermath.

A new report by the International Federation of Red Cross and Red Crescent Societies (IFRC) that examined various emergencies in Southeast Asia and asked the question “what happened next?” makes for grim reading. The researchers interviewed more than 1,800 survivors and aid workers who experienced events including Typhoon Haiyan in the Philippines in 2013, the 2016 earthquake in Aceh, North Sumatra, and chronic flooding in areas of Laos in 2016.

Nearly a third (30 per cent) of people surveyed in the Philippines said women and girls felt distressed by the rise in child marriage after the typhoon, while 27 per cent of people interviewed in Laos were aware of someone who had been raped following the disaster.

In Aceh, after a quake even more damaging than last week’s Lombok disaster, 13 per cent of respondents were distressed by the ensuing rise in domestic violence.

These findings make depressing reading, and come after the Oxfam aid scandal in which humanitarian workers were found to be sexually exploiting vulnerable women after the 2010 Haiti earthquake. But in these Asian disasters, the main perpetrators were male community members, strangers and husbands who were sheltering from the disasters themselves.

Nora Aboriantos, a volunteer aid worker who helps run a shelter for women and children in Dulag, a coastal town near Tacloban City in the central Philippines hit by Typhoon Haiyan, said she saw at least 30 cases of sexual abuse after the disaster – the youngest victim a two-year-old child. “This case was reported by her own parent and grandmother who were situated in a tent during that time,” she said. “I was shocked because this is a two-year old victim and her own grandfather is the perpetrator. It occurred to me, why do these kind of things happen? I immediately turned away from seeing the child and cried. I was touched emotionally because I also have a two-year-old child.”

Aboriantos, 47, said the child’s mother confided that she and her older sister had also been abused by the grandfather, but despite this, the family did not wish to press charges. “When we asked as to why they will not file a case, they responded that the perpetrator is more than 60 years old. They pity the grandfather if he will be put into jail at an old age.

“Also, the father of the child does not know anything about this and they are worried that if he knows, he will do something outrageous,” she said.

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Priyanda Bhalla, lead author of the IFRC report, said the risks of abuse and violence increased immediately after a disaster, often in the first 48 to 72 hours.

“It starts at the evacuation centre sites, which some people say are the places most at risk,” she said. “You may have hundreds of people squeezed into a small, crowded space like a refugee camp, or temporary shelters in schools, community centres, and they can remain there for weeks.”

Despite guidance on preventing these risks, she added, “we are still seeing poorly designed shelters. There is often little or no privacy, a lack of separate toilets with locks and no safe space for women and children.”

Globally, one in three women is affected by physical or sexual violence during her lifetime, mostly from partners. At the same time, 750 million women and girls alive today were married before the age of 18.

Women who survived disasters said the stress of losing homes, possessions and income leads to domestic violence or efforts to marry off daughters after sexual encounters, or because they were seen as a burden.

Dini Widiastuti, executive director of the Plan International Indonesia Foundation, which campaigns against child marriage and this week was among charities responding to the Mount Rinjani earthquake, said: “In Lombok, the incidence of early marriage is high already. Poverty means the girls are seen as a burden because they are not perceived as future breadwinners … we need to bear this in mind so that this disaster will not lead to a situation where more girls are married off early because the family lost their home.

“There is also a culture that after 6pm in the evening, girls and boys are not allowed to be together, to avoid bringing shame on the family,” she added.

“When the normal social structures break down after a disaster, there can be a risk that marriage results because suddenly young people are mixed together in close proximity.”

International aid agencies and governments have long been aware of these risks, but must do more to address the problem, Bhalla said.

“There is a need to take action now,” she said. “If the response to current emergencies is not well managed and does not take the risks of sexual and gender based violence into account, then these consequences will keep on happening.

“That is why the Red Cross is including child protection and gender inclusion in its current emergency appeals.”