Historical Seismograms - Evidence from the AD 2000 Izu Islands ...

164 Yushou Xieand is therefore more reliable. Another item in the same book recorded: “In thesecond year of Emperor You (about 780 B.C.), all the three rivers (Jinhe, Weihe andLuohe) quaked.. . , In this year, the three rivers exhaust,ed, Mount Qishan slided.”This item is more concrete in its contents and is generally consiclered to be reliable.Besides, we have collections of seismic niaterials since early clays, for example: achapter in “Taiping Yu Lan”, written by Li Fang in 977 A.D., collected 45 items ofearthquakes between the 11th century B.C. and 618 A.D.; the “Chapter on StrangeThings” in “General Reference to Literatures and Documents)’, selected by MaDuaiilin in the 13th century, collected 208 items of earthquakes between the 11thcentury B.C. arid the 13th century; the “Chapter on Telluric Abnormal Phenomena”in “Collection of Ancient arid hlodern Books”, written by Jiang Jianjiun andpublished in 1725, recorded 654 itenis of earthquakes, landslides and ground fissuresfrom the 11th century B.C. to 1722 A.D.Our historical materials contain not only earthquake phenorriena, but also accompanyingphenomena before, during and after their occurrences, the influenceof local conditions on the destructiveness of earthquakes, anti-seismic measures ofbuildings, methods to safcguard lives, arid philosophy of earthquake generation, e.g.in an imperial edict of Emperor Kaiigxi in the Qing Dynasty written in 1720, itwas said that earthquake is caused by the bursting of gas buried underground, thusseisrtiicity is high in North China where the overburden is thick. Of course, theycan not all be expected to be true. Especially the explanations are riot always scientific.But, througli systeiiiatic and objective analysis, they can inspire our trainof thoughts on earthquake prediction and mitigation of seismic hazards.3. Compilation of Historical MaterialsSince the founding of our People’s Republic, the assessment of seismic risk ofconstruction sites is of urgent need. As we had only a few seismic stations before1049, instrumental data are far from sufficient to solve such a problem. Under tlieunified leadership of the Central Government, specialists from related organizationsand scientific institutes organized expeditions and collected large amount of seismicmaterials from field work, as well as literatures and historical documents.On this basis, the Seismological Committee of Academia Sinica organized historiansand seismologists to further search for new materials. Within two years, theyread more than 8,000 various sorts of literatures and collected more than 10,000items of liistoricrtl inaterids concerning 880 destructive earthquakes. In 195G, theChronological Table of Chinese Earthquakes (Academia Sinica, Seismological Committee,1956) was published. This book of nearly two riiilliori words was highly valuedby seisniologists. They deemed that it has profound significance in the studyof seismicity and mitigation of seismic hazards. On tlie other hand, people alsodiscovered that there are iriiperfectioris in the materials collected and the editorialwork.Since the publication of the Chronological Table, seismological study has madegre at development in our country. Seismologists , historians , archeologists , arch i-vists, engineers and librariniis did a lot of collection, sortirig arid research workon historical earthquakes, and published various collections of historical recordsof earthquakes. Seismological organizations have been formed in all provinces,metropolis and autonomous regions of our country. Many of them linve collectedhistorical materials of earthquakes in their own regions.