地震工程学报
地震工程學報
지진공정학보
China Earthquake Engineering Journal
2014年
2期
405-412
,共8页
宝昌台%地电阻率%异常%地震%远距离
寶昌檯%地電阻率%異常%地震%遠距離
보창태%지전조솔%이상%지진%원거리
Baochang station%geo-electrical resistivity%anomaly%earthquake%long-distance
分析了内蒙古宝昌台地电阻率长期观测数据的可靠性,应用归一化变化速率方法和傅氏滑动方法处理了1985年以来的地电阻率观测数据,研究了该台在地震前中期、短期阶段的监测效能,结果显示:该台两个正交测道的地电阻率观测对台站周围的中等以上地震有一定的监测能力,表现出了与地震有关的震前持续性的中期、短期异常,且在中国大陆及周边发生的数次远距离8级以上大震前也记录到持续1年尺度时间的下降/上升异常。
分析瞭內矇古寶昌檯地電阻率長期觀測數據的可靠性,應用歸一化變化速率方法和傅氏滑動方法處理瞭1985年以來的地電阻率觀測數據,研究瞭該檯在地震前中期、短期階段的鑑測效能,結果顯示:該檯兩箇正交測道的地電阻率觀測對檯站週圍的中等以上地震有一定的鑑測能力,錶現齣瞭與地震有關的震前持續性的中期、短期異常,且在中國大陸及週邊髮生的數次遠距離8級以上大震前也記錄到持續1年呎度時間的下降/上升異常。
분석료내몽고보창태지전조솔장기관측수거적가고성,응용귀일화변화속솔방법화부씨활동방법처리료1985년이래적지전조솔관측수거,연구료해태재지진전중기、단기계단적감측효능,결과현시:해태량개정교측도적지전조솔관측대태참주위적중등이상지진유일정적감측능력,표현출료여지진유관적진전지속성적중기、단기이상,차재중국대륙급주변발생적수차원거리8급이상대진전야기록도지속1년척도시간적하강/상승이상。
Since the Xingtai earthquake in 1966,the geo-electrical resistivity observation has been implemented in a large scale in China.At present,approximately 90 geo-electrical resistivity sta-tions are in operation in mainland China as a result of network construction in the period from the seventh five-year plan to the tenth five-year plan.In the long-term observation,significant anoma-lies in geo-electrical resistivity have been recorded before the MS 7.8 Tangshan earthquake in 1976,the MS 7.2 Songpan-Pingwu earthquake in 1976,the MS 7.6/7.2 Lancang-Gengma earth-quakes in 1976,and the MS 8.0 Wenchuan earthquake in 2008.Moreover,several moderate-strong earthquakes have been accurately forecasted on the basis of geo-electrical resistivity observation. However,many people still have different understandings on the anomalies in geo-electrical resis-tivity before earthquakes due to lack of knowledge of earthquake preparation and occurrence processes,crustal structure,and medium conditions from the epicentral area to observation station and dynamical processes of underground media.Such confusion may be attributed to the small de-tecting depth/range of current DC geo-electrical resistivity stations and the complicated behaviors of anomalies in geo-electrical resistivity that include the anomalous changes caused by observa-tional environments.The Baochang geo-electrical resistivity station in Inner Mongolia has continu-ally observed for more than 30 years and has met the technical requirement of geo-electrical resis-tivity observation in China.Many moderate and great earthquakes have occurred near this sta-tion.This study evaluates the reliability of long-term geo-electrical resistivity observation data of the station by processing the data recorded since 1985 by using the normalized variation rate method and the Fourier sliding method for identifying earthquake-related anomalies in geo-electri-cal resistivity and studies the monitoring ability in the medium-term and imminent stages before an earthquake occurs.The research results are as follows:Baochang station has not been affected by the observational environment in the long-term.Its observation data are valuable in earth-quake scientific research and earthquake prediction,and the anomalies identified by the aforemen-tioned two methods are credible.We believe that the geo-electrical resistivity observation of sta-tion Baochang has certain monitoring ability for moderate-great earthquakes near the station.The geo-electrical resistivity of two orthogonal channels of the station has shown continuous medium-term and short-term anomalies around the station related to the earthquakes.Furthermore,the de-creasing or increasing anomalies which lasted for one year,were also recorded before the long-dis-tance MS 8.0 or above earthquakes that occurred near mainland China and its surrounding area, which were historically well corresponded to the occurrence of the great earthquakes.