Suzuka wrote about it on a Sakura Gakuin diary post on April 1st, 2011. It is translated below (credit to Hello-online user k439b):
What I think now
“March 11, there was unbelievable big earthquake occurred in Japan. There are many sufferers in Eastern Japan and still live in difficulties that are painful for all people in Japan and in the world.
On that day, I was in Japan. I worried so much because trains had stopped and cell phones did not work. But many people protected me and I was OK.
While I was in Tokyo, there were still many small earthquakes and blackouts. Exchanging mails with Sakura Gakuin members and Airi chan being with me all the time made me feeling safe.
Airi chan could not make a contact with her family for a long time, but she hided her anxiousness for me. I found Airi chan is very strong and I respect her from my heart.
Four days later, while I was not what was happening in detail, I came back to Hiroshima. I finally found how it was serious by watching TV. I was very scared because everything was unbelievable and it did not seem like Japan. I felt shame that I did not know anything and I did not do anything.
All people in Japan are doing what they can do. I though very much what I can do as a girl living in Hiroshima.
I do not have so much money, but I decided to donate my saved 1 yen coins for four years. I heard that it may take more than ten years to be recovered. What I can do now may not be a lot, but every time I found something that I can do, I will do it.
Thousands of small power can be a big power I believe.
My town Hiroshima lost everything in the past and recovered.
It was the time before I born, current town has rebuild from nothing which I still cannot believe from the old photos. So I believe that current situations cannot be believed by future people.
I pray that sad things will not happen any more.
I think there are many people including Sakura Gakuin members and fans supporting us still are working in the difficult situations. I hope the day soon comes that we can sing together with laughter.”
Here is a video where Su mentions her coin collection (at 0:15):