5 events the sources record for this year, grouped by region.
What happened
China (2)
Li Jingxuan and Liu Shenli fought the Tibetans on the banks of the Qinghai and were defeated, and Liu Shenli was taken prisoner. (Old Book of Tang (Jiu Tangshu), Annals 舊唐書 卷5 儀鳳3年 9月)
In September 678 (Bingyin day), Li Jingxuan, with 180,000 men, fights Tubo's Lun Qinling by the shore of Qinghai and is defeated; Minister of Works Liu Shenli is captured by Tubo. (Zizhi Tongjian (Comprehensive Mirror) 권202 678년 항)
Japan (1)
In the twelfth month of year 7 (678), a great earthquake struck Tsukushi province; the ground split two jō wide and over 3,000 jō long, and houses collapsed. (Nihon Shoki (Chronicles of Japan) 日本書紀 卷第廿九 天武紀 7年 단락183)
In August a comet was visible for three months; Bishop Wilfrid was driven out by King Ecgfrith, and Bosa and Eata were consecrated in his place. (Anglo-Saxon Chronicle Giles/Ingram 1847 A.D. 678 항 (pg657.txt 줄 1842))