The utility has slowly accepted the contention of Ms. Ashiharaâs group by repeatedly increasing its estimate of the size of the fault. Yet a district court last year ruled in favor of Chugoku Electric Power, accepting its argument that its estimates were based on the better scientific analysis. âWe jokingly refer to it as the ever-growing fault line,â said Ms. Ashihara, 58, who works as a caregiver for the elderly. âBut what it really means is that Chugoku Electric does not know how strong an earthquake could strike here.â Her group filed the lawsuit in 1999, a year after the operator suddenly announced that it had detected a five-mile-long fault near the plant, reversing decades of claims that the plantâs vicinity was free of active faults. Chugoku Electric said the fault was too small to produce an earthquake strong enough to threaten the plant, but Ms. Ashiharaâs suit cited new research showing the fault line could in fact be much longer, and produce a much stronger earthquake.