Why was the fire engines prevented from going to help?

Read the passage and circle the best answer to each of the following questions about it

Almost a hundred thousand people were killed and half a million homes destroyed as a result of an earthquake in Tokyo in 1923. The earthquake began a minute before the noon when the inhabitants of Tokyo were cooking their midday meals. Thousands of stoves were overturned as soon as the earth began to shake. As a result, small fires broke out everywhere and quickly spread. The fire engines were prevented from going to help because many of the roads had cracked open. It was impossible to use fire fighting equipment as most of the water pipes had burst. Consequently, over ninety percent of the damage caused by fire rather than by the collapse of the buildings.

Why was the fire engines prevented from going to help?