Based on the results of field geological surveys and stratigraphic dating data, the paleo-sandblows and their represented paleoseismic events developed in the upper strata of the Taoyuan Basin were analyzed. More than ten paleo-sandblow traces were outcropped in the 7-km-range from Taoyuan to Xialinong region in the Taoyuan Basin. The sandblows and their deposits are featured by mushroom-shape, umbrella-shape, sac-shape and skewed cup shape. Their large scale and wide distribution indicated that there was a strong sandblow eruption events related to paleoearthquake. The width of sandflow depositsis several meters, and the thickness is tens of centimeters to one meter. The largest one is 8 meters wide, and 1–1.5 m in the thickness. It is common to observe 1.0–4.5 m long, 0.25–0.35 m in diameter, and 0.8 m in width sand veins. The paleosol layer with good continuity is generally developed at the depth of 1.5–3.0 m below the ground, which is the ground surface at that time. These sand veins and sandflow deposits are generally developed above and below this layer. According to the 14C dating results of the top of the paleosol layer and the bottom of the overlying strata of the sandflow deposits, it is speculated that the time of the paleoseismic event forming the sandblows is 13030±40–12120±40 aBP, and its magnitude is at least greater than 7. The Chenghai-Binchuan fault was a strong active fault in the late Quaternary period, which triggered this Taoyuan earthquake.

根据野外地质调查结果和地层测年数据, 分析涛源盆地上部地层中的古砂脉及其代表的古地震事件。涛源至下力农东西长7 km的范围内集中分布十余处古砂脉, 砂脉及砂流堆积呈蘑菇状、伞状、囊状和歪斜的水杯状, 砂流堆积规模大, 分布广, 暗示该区域发生过强烈的喷砂冒水事件。砂流堆积宽数米, 厚数十厘米至1 m左右, 最大堆积宽度和厚度分别为8 m和1.0~1.5 m; 砂脉长1.0~4.5 m, 直径为0.25~0.35 m, 最大宽度为0.8 m。地面以下1.5~3.0 m深度普遍发育连续性较好的古土壤层, 代表砂脉形成时期的地表面。这些砂脉及砂流堆积普遍赋存在古土壤层的上下部位。据古土壤层顶部和砂流堆积上覆地层底部的14C测年结果, 推测形成砂脉的古地震事件时间为13030±40~12120±40 aBP, 震级大于7级。程海–宾川断裂为晚第四纪强烈活动断裂, 并引发此次涛源大地震。