Book 12 of The Tale of the Heike begins with an account of the Great Earthquake of 1185. It describes the Earthquake as causing great damage to the capital, including the destruction of portions of the capital and many shrines, as well a calamity across Japan. The chapter ends by saying:
Just as the cause of the earthquake is attributed to the actions of the Genji, karmic retribution in the form of natural disasters is present in many Japanese stories.
As Gennifer Weisenfed states, "Most Japanese people from the premodern period...believed natural disasters were...caused by social impurities directly linked to human behavior."[1]
Other possible karmic disasters which occur in The Tale of the Heike is the food shortage that is present throughout the story and in Episode 11 of Book 6 when Jo no Taro Sukenaga is leading troops to fight Yoshinaka but is confronted with a storm that shouts that he is an ally of the Heike who burned the Roshana Buddha. When Sukenaga refuses to call off his attack, a black cloud enshrouds him and he dies. Sukenaga's death is due to force of nature, but like the Great Earthquake, it is attributed to human fault, in this case Shigehira's burning of Nara.
[1] Weisenfeld, Gennifer S. Imaging Disaster: Tokyo and the Visual Culture of Japan's Great Earthquake of 1923. 1st ed., Univerity of California Press, 2012.