But it is the picture of the first ShelterBoxes containing disaster relief tents arriving in Sri Lanka by raft that is the resounding image for Mark when he reflects on the fifth anniversary of one of the world's worst disasters ever witnessed.
Just days after the tsunami hit following a massive undersea earthquake off the Indonesian coast, Mark was in Batticaloa, east Sri Lanka, co-ordinating the distribution of aid for the international disaster relief charity ShelterBox. Several weeks later he was also deployed to Banda Aceh, Indonesia, to help distribute emergency shelter to thousands more people.
Mark, 37, who was born in Ayrshire and now lives in Cornwall, said: 'It was incredible to see how much destruction there was. It was monumental. In Banda Aceh there were fishing boats five miles from the sea and towns and cities that had been wiped off the map.
'Nothing could have been more powerful than the tsunami. This was the biggest disaster anyone of us will see in our lifetimes.
'But the picture that stands out for me personally is of the first ShelterBoxes arriving in Ulle, Sri Lanka, where a bridge had been destroyed by the tsunami. We had help from the Sri Lankan Navy and the Canadian Army Logistics Corps who built a raft so we could transport the ShelterBoxes. It was good to know we were starting to deliver help to thousands of people who had been displaced by the devastation.'
On December 26, 2004, an undersea earthquake struck the coast of Sumatra, Indonesia, triggering a series of deadly tsunamis. The earthquake had a magnitude between 9.1 and 9.3 on the Richter Scale - the second largest seismic activity ever recorded. Almost 230,000 people in 11 countries were killed in the tsunami and millions were left homeless.
In the months following the disaster, ShelterBox delivered tents and emergency supplies to thousands of people who had lost their homes in Sri Lanka, Indonesia, India and the Maldives.
Tom Henderson, ShelterBox's Founder and CEO, said: 'On 26 December 2004, news came in of the devastating Boxing Day tsunami and ShelterBox faced its most significant challenge, one that would change our course forever. Donations and volunteers poured in and we were able to ramp up our operations on a scale unimaginable just six months earlier.
'ShelterBoxes were sent to Indonesia, Sri Lanka, India and the Maldives and we were able to provide emergency shelter to thousands of people. But the human suffering from that day endures and five years on from the tsunami we remember the friends, families and loved ones who lost their lives in this tragedy.
'Everyone involved with ShelterBox remains deeply grateful for all the support received from donors and volunteers around the world. We have continued to build on our experience responding to the tsunami, helping as many people as we can and as quickly as we can, the moment disaster strikes.'
For more information on ShelterBox or to interview Mark Pearson, please contact Angelina Lambourn on +44 (0)1326 569782 or email AngelinaL@shelterbox.org.
To see the pictures
NOTES TO EDITORS
ShelterBox is an international disaster relief charity specialising in emergency shelter provision. Humanitarian aid is delivered in iconic green ShelterBoxes. Each one contains a disaster relief tent for up to 10 people, a stove, blankets and other items essential for survival. ShelterBox responds to disaster as quickly as possible with the aim of helping the people who are most in need.
Every box is individually numbered and can be tracked by donors. Each box costs £490 - including the cost of all materials, packing, storage, transport worldwide and distribution to the needy. Assuming six months' use, this equates to shelter and warmth for less than 30 pence per person per day.
All aid delivery is undertaken by international volunteer ShelterBox Response Team members who have carried out extensive training with ShelterBox. We are often able to get aid where it is needed faster than any other organisation.
An initiative of Rotarian Tom Henderson, a former Royal Navy search and rescue diver, ShelterBox started in 2000 as a project of the Rotary Club of Helston-Lizard, Cornwall. ShelterBox, now the largest Rotary Club project in the world, has responded to disasters including the Indian Ocean Tsunami, Hurricane Katrina and Cyclone Nargis in Myanmar (Burma). In 2010, ShelterBox will be celebrating its 10-year anniversary.