# Unusual Animal Behavior as a Possible Candidate of Earthquake Prediction
## 5 Our Latest Result for a Particular Tokyo EQ on 7 October 2021
### Minami-Boso Station
#### 5.2.3 Summary of the Observed Results on Cows' Milk Yield  
Four monitoring stations of daily cows' milk yield have been investigated: (1) Chiba-shi station (D = 15 km), (2) Isumi station (D = 48 km), (3) Asahi station (D = 57 km), and (4) Minami-boso station (D = 63 km), in the order of small to large epicentral distance of the stations from the EQ epicenter of the Tokyo EQ on 7 October 2021. Changes of cows' milk yield have been detected with the use of conventional statistical analysis based on our criterion. We can summarize the results as follows:  
1. Conspicuous changes in daily cows' milk yields at the closest station of Chiba-shi with D = 15 km were observed. At this station, a very clear depletion in cows' milk yield was detected during a period of a few days from 26 September to 28 September. The maximum depletion was observed on 27 September (or 9 days before the EQ), and the degree of depletion was the greatest, exceeding \(-3\sigma\), definitely because of the shortest distance from the EQ epicenter. 2. On the other hand, the behavior of cows' milk yields at farther stations of Isumi (D = 43 km), Asahi (D = 57 km), and Minami-boso (D = 63 km) looks very variable, in such a way that Minami-boso, at the farthest distance, yielded a significant anomaly and Isumi exhibited a small anomaly exceeding \(-1.5\sigma\), with no effect at Asahi. 3. The lead times for some stations are found to be 8-14 days, which seems to be very consistent with our previous statistical work [52; 53; 56]. 4. Multi-stationed monitoring of cows' milk yields is of crucial importance as a means of short-term EQ prediction. 2.4 Sensory Mechanism of Animals Based on a Comparison of Anomalies of Cows' Milk Yield with Electromagnetic Anomalies for This EQ  
This target Tokyo EQ has already been extensively investigated by using multi-parameter electromagnetic observations [46]. As is described in [PERSON] et al. (2022) [46], the people in the Tokyo district are afraid of the next huge EQ since the 1923 Kanto (Tokyo) devastating EQ, so we wanted to explore whether there exists any EQ precursors to a model EQ (M = 5.9) like this Tokyo EQ on 7 October 2021. Here we will review their multi-parameter observations for this Tokyo EQ, which include various physical parameters for the three layers of the Earth, such as (i) lithospheric ULF radiation (lithospheric parameter), (ii) lower atmospheric parameters (meteorological parameters (T (temperature)/Hum (humidity), ACP (atmospheric chemical potential), and ULF/ELF atmospheric radio emissions), (iii) stratospheric AGW (atmospheric gravity waves), (iv) lower ionospheric perturbations (studied by two independent phenomena of ULF depression and subionospheric VLF/LF propagation anomalies), and (v) upper ionospheric parameter (NmF2 (ionosonde) and GPS (Global Positioning Satellites) TEC (total electron content)). These electromagnetic phenomena will be investigated with special reference to their comparisons with those of cow's milk yield changes in order to better understand the sensory mechanism of animals. Figure 3 is depicted as a graph, based on the summary table in [PERSON] et al. (2022) [46]. We have also included the anomalies of dairy cows' milk yield for the sake of comparison in the top part of Figure 3. Here we will compare the temporal variations of cows' milk yields with those of different electromagnetic effects, starting from the upper atmosphere to the lowest region of lithosphere. As seen from Figure 3, it is found that the ionosphere is not perturbed in the upper F region, but only the lower ionosphere is perturbed just before the EQ when using two independent methods of subionospheric VLF propagation anomalies and ULF depression effect, and only just around the EQ (with VLF subionospheric propagation anomalies), i.e., a few days before and after the EQ. A subionospheric VLF anomaly is observed in Chofu (Tokyo) with the signals from the Australian NWC (North West Cape) transmitter as the reliable evidence of lower ionospheric perturbation.