Answer by taking a quote from the following article:

The son of well-known surfer Jeff Johnson, Jack was born and raised on the North Shore of Oahu, Hawaii. He began to learn how to surf at the age of five. At seventeen he became the youngest invitee to make the finals of the Pipeline Masters, one of surfing's most prestigious surfing events, on Oahu's North Shore. One week later, however, his stint as a professional surfer ended when he suffered a surfing accident at the Pipeline that put more than 150 stitches in his forehead and removed a few of his teeth; this later became the inspiration for the song "Drink the Water".

In 2008, Johnson and his wife Kim created the Johnson Ohana Charitable Foundation, a non-profit public charity supporting environmental, art, and music education worldwide. Jack and Kim Johnson also founded the Kokua Hawaii Foundation in 2003. Johnson and his family work hard every year at festivals and concerts alike, to raise money for causes they feel are most important. Johnson recorded a cover of John Lennon's "Imagine" for the 2007 benefit album Instant Karma: The Amnesty International Campaign to Save Darfur, which was also included on the 2009 benefit album Rhythms del Mundo Classics. In talking about Johnson and his career choices, Rolling Stone wrote: "It is a typically generous move from Johnson, who has used his multi-platinum success to support causes he cares about." Although the Johnson Ohana Charitable Foundation is a non-profit organization that "focuses on environmental, arts and music education", it has raised more than $750,000 from 2009 to 2010 to give away. Johnson was in Osaka, Japan on his To the Sea 2010 World Tour at the time of the 2011 Tohoku earthquake and tsunami in northern Japan. He was in a hotel with his family when it struck. After having to postpone the rest of his tour, he donated $50,000 to GlobalGiving's Japan Earthquake and Tsunami Relief Fund. Johnson's Ohana Charitable Foundation has also supported Little Kids Rock, a national nonprofit that works to restore and revitalize music education in disadvantaged U.S. public schools. He also decorated a guitar for Little Kids Rock to auction to raise funds for its program. On September 22, 2012, he donated his time to play a few songs at Farm Aid 2012 in Hershey, PA. Later in 2012, Jack donated $50,000 for Hurricane Sandy relief and added links on his website for others to donate:

Did he help raise any money for other catastrophes ?
raised more than $750,000 from 2009 to 2010 to give away. Johnson was in Osaka, Japan