The outside world scarcely knew of north-western North America in the year 1700. The Pacific coast, from south-central Alaska to Oregon's Cape Blanco, was uncharted until the Spanish and English explorations of the 1770s. Yet, when tectonic plates suddenly shifted there in 1700, a train of ocean waves - a tsunami - sped across the Pacific Ocean. When the waves came ashore in Japan, they flooded fields and washed away houses. Samurai, merchants, and villagers recorded the mysterious event, but they observed no storm and felt no parent earthquake. In Japan, this tsunami was an orphan. "The Orphan Tsunami of 1700" tells this transpacific detective story by presenting its primary sources, Japanese documents and North American sediments and tree rings. They tell of a catastrophe, a century before Lewis and Clark's expedition, that now guides preparations for future earthquakes and tsunamis in the North Pacific. A rich array of graphic detail and narrative explains the creation, action, and lasting effects of earthquakes and tsunamis.