However, with the study of Sanxingdui site for decades, there are different explanations and statements about the reasons for Sanxingdui's disappearance. There are mainly earthquakes and floods.
The view of seismology is that Sanxingdui civilization suffered great trauma after the earthquake, and the original suitable living environment was gone, which forced Sanxingdui people to abandon their original homes and choose other places to survive. So is the flood theory. According to this view, the Bashu area where Sanxingdui is located was abundant in ancient times, and the flood disaster should have appeared before Dujiangyan and other water conservancy projects appeared, so Sanxingdui civilization disappeared in a major flood disaster. Of course, these two statements are only guesses at present, and experts have not found any traces of floods or earthquakes in archaeological excavations.
As for why Sanxingdui civilization suddenly disappeared, it needs a lot of excavation and scientific analysis to get the result. Many cultural relics unearthed now show certain rules, and these cultural relics are damaged to a certain extent, but these tombs show certain rules. These laws show that when they left Sanxingdui, they were not forced by very urgent circumstances. Therefore, some people speculate that the reason for their disappearance is that Sanxingdui civilization had to transfer its political center because of other choices of interests.
In addition to the above, I personally think that Sanxingdui civilization has not disappeared, but has integrated into the whole Chinese civilization and become a part of it.
What I said is mainly based on the close relationship between Sanxingdui civilization and Central Plains civilization. A large number of bronzes unearthed from Sanxingdui site can be found to have the same or similar cultural symbols as the Shang civilization in the Central Plains at the same time, which shows that Sanxingdui civilization was not a closed social system at that time, and they had strong cultural exchanges and even trade exchanges with the Central Plains civilization. Therefore, with the changes of times and time, Sanxingdui civilization has gradually merged into the whole Chinese civilization, but due to the lack of corresponding written records, the specific historical situation of Sanxingdui civilization in its early stage is still unknown.