It was also declared the International Women's Year by the United Nations and the European Architectural Heritage Year by the Council of Europe. Events January January 1 - Watergate scandal (United States): John N. Mitchell, H. R. Haldeman and John Ehrlichman are found guilty of the Watergate cover-up. January 2 The Federal Rules of Evidence are approved by the United States Congress. Bangladesh revolutionary leader Siraj Sikder is killed by police while in custody. A bomb blast at Samastipur, Bihar, India, fatally wounds Lalit Narayan Mishra, Minister of Railways. January 5 – Tasman Bridge disaster: The Tasman Bridge in Hobart, Tasmania, Australia, is struck by the bulk ore carrier , killing 12 people. January 7 – OPEC agrees to raise crude oil prices by 10%. January 10–February 9 – The flight of Soyuz 17 with the crew of Georgy Grechko and Aleksei Gubarev aboard the Salyut 4 space station. January 15 – Alvor Agreement: Portugal announces that it will grant independence to Angola on November 11. January 19 – The 6.8 Kinnaur earthquake affected Himachal Pradesh in India with a maximum Mercalli intensity of IX (Violent), killing 47. January 20 In Hanoi, North Vietnam, the Politburo approves the final military offensive against South Vietnam. Work is abandoned on the British end of the Channel Tunnel. January 24 – Jazz pianist Keith Jarrett plays the solo improvisation The Köln Concert at the Cologne Opera. The live recording becomes the best-selling piano recording in history. February February 4 – The Haicheng earthquake, the first successfully predicted earthquake, kills 2,041 and injures 27,538 in Haicheng, Liaoning, China. February 5 – The Argentinian president Isabel Perón decrees Operativo Independencia, aiming to neutralize or annihilate the "subversive elements" in the province of Tucuman. Isabelita takes advantage to take a self-coup and assume extraordinary powers. February 11 Margaret Thatcher defeats Edward Heath for the leadership of the opposition UK Conservative Party. Thatcher, 49, is Britain's first female leader of any political party. Colonel Richard Ratsimandrava, President of Madagascar, is assassinated. February 13 – A "Turkish Federated State of North Cyprus" is declared as an unsuccessful first step to international recognition of a Turkish Cypriot separatist state in Cyprus. February 21 – Watergate scandal: Former United States Attorney General John N. Mitchell, and former White House aides H. R. Haldeman and John Ehrlichman, are sentenced to between 30 months and 8 years in prison. February 27 –