We make trial binary forecasts for the Kurile–Japan subduction zone for the period 1988–2014 by hypothesizing that seismic quiescence (i.e., the absence of earthquakes of M ≥ 5 for a minimum period of T_q) is a precursor of a large (7.5 ≤ M_w < 8.5) earthquake in the coming period T_a within a radius R of the quiescence. We evaluate the receiver-operating-characteristic diagram constructed using a range of forecast models specified by (T_q, R, T_a). A forecast experiment targeting eight large earthquakes in the studied spacetime suggests that the risk of a large earthquake is modestly (probability gain G ~ 2) but significantly (p-value less than 5%) heightened for several years following a long quiescent period of T_q ≥ 9 years, within several tens of kilometers of the quiescence. We then attempt cross-validation, where we use half the data for training [i.e., optimization of (T_q, R, T_a)] and the remaining half for evaluation. With only four target earthquakes available for evaluation of the forecasts in each of the learning and evaluation periods, our forecast scheme did not pass the cross-validation test (with a criterion that the p-value is less than 5%). Hence, we cannot formally deny the possibility that our positive results for the overall period are a ghost arising from over-fitting. However, through detailed comparison of optimal models in the overall test with those in the cross-validation tests, we argue that severe over-fitting is unlikely involved for the modest G of ~ 2 obtained in the overall test. There is thus a reasonable chance that the presently tested type of quiescence will pass the cross-validation test when more target earthquakes become available in the near future. In the meantime, we find that G improves to ~ 5 when target earthquakes are limited to 8 ≤ M_w < 8.5, though we cannot say anything about the possible involvement of over-fitting because we have only three such very large target earthquakes.

我们通过假设到该地震平静（即，不存在地震使这一期间1988年至2014年的千岛-日本俯冲带试验二进制预报中号 ≥5的最小周期Ť _q）是一个大的前体（7.5 ≤ 中号_瓦特 <8.5）在未来一段时间内地震Ť_一个半径范围内- [R的静止的。我们评价使用范围由（指定的预测模式的接收器操作特征图构造Ť _q，- [R ，Ť_一个）。预测实验中所研究的时空靶向8级大地震表明，大地震的风险是温和（概率增益G ^  〜2）但是显著（p -值小于5％）增强，用于以下的长静止期几年Ť _q≥9年 ，在静止的几十公里内。然后，我们尝试进行交叉验证，在交叉验证中，我们使用一半的数据进行训练[即（（T _q，R，T _a）]，其余一半用于评估。在每个学习和评估阶段中，只有四个目标地震可用于评估预测，因此我们的预测方案未通过交叉验证测试（p值小于5％的标准）。因此，我们不能正式否认我们整个时期的积极结果是因过度拟合而产生的假象的可能性。但是，通过将整体测试中的最佳模型与交叉验证测试中的最优模型进行详细比较，我们认为对于适度的G，不太可能出现严重的过度拟合在整体测试中获得的〜2。因此，在不久的将来有更多目标地震出现时，当前测试的静态类型就有可能通过交叉验证测试。在此期间，我们发现，G ^提高到〜5时，目标地震仅限于8≤ 中号_{w ^}  <8.5，虽然我们不能说的过度拟合，因为我们只有三个这样的非常大的目标的地震可能参与任何东西。