The ケラヴァ(Kerava) spelling appears to be slightly more common in online usage than ケラバ(Keraba), and the use of the ヴァ(va)digraph immediately marks this word as a foreign borrowing. However, for most Japanese speakers, the pronunciation will be closer to ケラバ(Keraba), due to the lack of any /v/ phoneme in the native Japanese consonant inventory.