Librarian Penny Walsh poses among the books that were thrown from their shelves after last nights earthquake in Gisborne December 21, 2007. A series of aftershocks rattled the New Zealand city of Gisborne on Friday as officials assessed damage caused by the country's strongest earthquake in 20 years, which injured several people. The 6.8 magnitude quake struck the city on the east coast of the country's North Island just before 9 p.m. on Thursday (0800 GMT), sending people to higher ground and disrupting power, phone and water services. REUTERS/Gisborne Herald (NEW ZEALAND) NEW ZEALAND OUT. EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS.