A volunteer's volcanic activityAn Earthwatch volunteer ran a 26-mile marathon, and then cycled the same distance immediately afterwards, to help to raise money for her expedition with Earthwatch.

When Rebecca Pearson from Exeter decided to join the Earthwatch expedition Volcano in February 2010, she asked friends and family to sponsor her to help to pay for part of the cost. On Saturday 17 October she ran the marathon at her local gym, the Riverside Leisure Centre, in four hours 53 minutes, and then cycled the same distance in one hour 23 minutes.

Rebecca, 28, said: "I have so far raised approximately £120 from friends and family, and also from a donation 'bucket' on the day that people were putting change into (I think they felt sorry for me!). I still have some more money to collect in yet and hope to raise about £200 in total from this. My total time was six hours 16 minutes."

She added: "I had a couple of friends do a bit of running and cycling alongside me to try and keep me going, but did most of it alone, apart from hubby and kids coming in now and again to cheer me along. I had only done about seven weeks training for this. The idea was just one of my 'why not' kind of ideas. It was also a personal challenge for me as I never thought I would be able to do it."

Rebecca chose the Volcano expedition as not only is she passionate about trying to do all she can to help protect the environment, but is currently studying for a degree in geosciences with the Open University and therefore has a huge amount of scientific interest in the expedition.

"This is how I found out about Earthwatch and the expedition (which is my first one, but most likely not my last!). I received an email from the university about the expedition, and booked it within minutes of reading about it, as the lead scientist, Dr Hazel Rymer, is an Open University lecturer."

Rebecca, who has not worked since starting a family two years ago, is no stranger to adventure. She started her working life as an outdoor pursuits instructor and her previous jobs have included work as a builder, and dangling from buildings and bridges in her role as an industrial abseiler.

• Dip into our fundraising pack to find out how you can raise money for Earthwatch and help to pay for your Earthwatch expedition.