I would recommend looking into construction methods in flood-prone areas. Specifically building on stilts as well as ram filled earth-dykes etc.
This is assuming periodic small eruptions. For large eruptions, I suggest they pray to their deity.
I believe a history of living in the area would make sense if you follow a logical progression in defensive capabilities.
At first the people migrated around the volcano whenever it was erupting. Avoiding the dangerous areas and settling in a new location still on the slopes of the beloved deity.
Then they slowly become stubborn (really holy) and want to build a temple to their beloved that will withstand her (it's a female deity right?) ...hiccups. So they try a few different temples.
First one made of finely carved woods from all over the island. Unfortunately it burnt to ashes on the next lava flow in the area.
The second attempt they built a level of stone and then the finely carved wooden temple on top of that. Unfortunately that also caught alight on the next flow. The lava was stopped for a short time by the stone level but the stone was not thick enough as the lava gathered and accumulated in the vicinity before flowing off on the sides. The wooden temple also caught fire just from the excessive heat of the nearby lava. The locals learnt two things from this, when lava is obstructed, it grows in height before finding a new outlet and wood can burn even if not in direct contact with the heat source.
So they try again. This time they try and elevate the temple on multiple stone pillars. This allows the lava to flow mainly unobstructed and it doesn't gather and grow in height. After a few attempts, the design of the pillars incorporates various features such as wider on the side where the lava is most likely to flow from (incase the stone actually melts and gets eaten away), directional buttresses to direct flow in certain directions etc.
Either at the same time as developing the pillar design they also start building walls. They want to have some village halls and grain stores etc near their temple. Ie they are developing a settled village/town design rather than roaming around the volcano slopes.
The first walls are earthern embankments. After a few failures they realise you need a sharp slope on the outside and a thick gentle slope on the inner wall. Stone lining the sharp outer bank helps. The lava still grows if obstructed for large lengths so they figure out that they should build their walls V shape, not curved. This allows the lava to be pushed into a direction the villagers want. But a thin V shaped village design is not ideal.
After awhile the villagers want to expand. They build a second wall. And then a third. (The temple always has the most protection). They think they are clever, and leave a lined gap between each chevron to allow tempoary access to the flow. They line this gap with straight walls running through the length of their village. I don't know if this ends in disaster but it probably will. Once the lava has cooled and solidified the villages will have to either build more walks or try and take a pick ax to the stone to clear their protection features.
They then realise it's best to have a series of protection chevrons further away from their growing village. These chevrons will be placed in sequence so that they take up the slack etc. The main village having a further protective wall of some design.
In summary, The end result is that important buildings are built on stone stilts with protective buttresses. The most impirtant could be completely made of stone, or at least the lower levels. They are typically placed in the most protected areas directly behind the chevron walls. There are large open streets to act as emergency funnels as well as further directional wall features inside the village/city to direct any lava that does make it into the area.
I'll try find some diagrams later to help explain my thought processes.
