The earthquake that shook the ancient city of Bam in Iran last December is thought to have killed at least 45,000 people. Allan Bell, an Australian working for Oxfam in Great Britain, is in Iran to lead Oxfam's emergency response to the disaster. It is not the first time Allan has responded to an emergency - the humanitarian co-ordinator worked for more than four months in Gujarat, India following the earthquake in 2001.

When I was working in Gujarat, I met a villager who told me he had been on his way to work when the earthquake struck one January morning. He told me how he watched the ground come rippling towards him – followed by a terrifying noise.

Of course, no two earthquakes are the same and the Gujarat earthquake was one of the largest of modern times, but the evocative image that villager conjured up will stay with me forever. The moment I heard the news about Bam, I knew it was going to be a terrible tragedy for Iran.

Entire families had been wiped out and the city had been virtually flattened. Now that we know the scale of the impact, it has become clear that around 85 per cent of housing was lost in the quake, with a total loss of around 45,000 lives.

Invariably earthquakes always hit the poorest the hardest because they can't afford the latest housing designs and in Bam, the material of choice for building is mud, which is always susceptible to damage.

In Gujarat the earthquake happened at around 8.30am when people were up and about and on their way to work. But in Bam, the earthquake struck during the early hours of the morning, when people were still asleep in bed. That's why there has been such a loss of life – people weren't even awake.

The infrastructure of Bam needs to be completely rebuilt, with housing a major problem. Oxfam is working with other international aid agencies and our short and medium-term roles are focusing on sanitation.

Sanitation is a basic part of everyday life that we all take for granted. The problems start when it's lost – diarrhoeal diseases such as dysentery and cholera can easily spread.

Reality is starting to set in for some people who are gradually coming to terms with the fact that their homes have been destroyed and they have lost everything. Bam is a grieving city and though people will be slowly trying to find some sort of normality, they will be coping with the fact that life will never be the same again.

Story based on a diary written by Allan Bell, humanitarian co-ordinator for Oxfam Great Britain. Donations to Oxfam Community Aid Abroad's International Crisis Fund will help support an international Oxfam emergency operation in Iran.

• Oxfam is part of an international relief effort in Iran, co-ordinated by the International Federation of the Red Cross and Red Crescent Society. Oxfam is focusing on water and sanitation to prevent the spread of disease.
• Oxfam has flown out a 70,000 litre steel water tank to Bam which has been installed alongside a field hospital run by the Iranian Red Crescent Society. Smaller tanks also flown into Bam by Oxfam have been used to transport water around the earthquake zone on trucks co-ordinated by the Iranian Red Crescent Society.
• To improve sanitation, Oxfam is providing 1,000 latrines and 500 constructed bathing and laundering facilities, which should support around 10,000 people.

For up-to-date information on our response in Iran, visit www.oxfam.org.au/world/emergencies. To make a donation to our International Crisis Fund, please call 1800 088 110 or visit our website.