The state straddles three different composite tectonostratigraphic terranes. The larger part of the state lies on the Central Maine composite terrane, comprising the Central Maine trough in the east and the Bronson Hill mantled gneiss domes in the west. A small area belongs to the Hurricane Mountain belt and olistostrome belt. The northernmost corner of the state lies within the Connecticut Valley trough of the Boundary Mountains composite terrane. In the coastal region in the southeast is the Merrimack-Orrington Belt of the Nashoba-Casco-Miramichi composite terrane.
Geography
The state is bounded by Quebec, Canada, to the north and northwest; Maine and the Atlantic Ocean to the east; Massachusetts to the south; and Vermont to the west. New Hampshire's major regions are the Great North Woods, the White Mountains, the Lakes Region, the Seacoast, the Merrimack Valley, the Monadnock Region, and the Dartmouth-Lake Sunapee area. New Hampshire has the shortest ocean coastline of any U.S. coastal state, with a length of, sometimes measured as only. New Hampshire was home to the rock formation called the Old Man of the Mountain, a face-like profile in Franconia Notch, until the formation disintegrated in May 2003. The White Mountains range in New Hampshire spans the north-central portion of the state, with Mount Washington the tallest in the northeastern U.S. In the flatter southwest corner of New Hampshire, the landmark Mount Monadnock has given its name to a class of earth-forms – a monadnock – signifying, in geomorphology, any isolated resistant peak rising from a less resistant eroded plain. Major rivers include the Merrimack River, which bisects the lower half of the state north-south and ends up in Newburyport, Massachusetts. Its tributaries include the Contoocook River, Pemigewasset River, and Winnipesaukee River. The Connecticut River, which starts at New Hampshire's Connecticut Lakes and flows south to Connecticut, defines the western border with Vermont. The state border is not in the center of that river, as usually the case, but at the low-water mark on the Vermont side; meaning that the entire river along the Vermont border lies within New Hampshire. Only one town – Pittsburg – shares a land border with the state of Vermont. The "northwesternmost headwaters" of the Connecticut, now known as Halls Stream, define Canada's border with New Hampshire. The Piscataqua River and its several tributaries form the state's only significant ocean port where they flow into the Atlantic at Portsmouth. The Salmon Falls River and the Piscataqua define the southern portion of the border with Maine. The largest of New Hampshire's lakes is Lake Winnipesaukee, which covers in the east-central part of New Hampshire. Umbagog Lake along the Maine border, approximately, is a distant second. Squam Lake is the second largest lake entirely in New Hampshire. New Hampshire has the shortest ocean coastline of any state in the United States, approximately long.. About offshore are the Isles of Shoals, nine small islands.
Earthquakes
While New Hampshire, along with the rest of New England, does not frequently experience earthquakes, it has experienced several in history and has been affected by some of the larger events that were centered in the Saint Lawrence rift system in Canada. One of these was the 1663 Charlevoix earthquake that was centered near the Quebec–Maine border, the magnitude of which has since been estimated at 7.3–7.9. In 1727, Newbury, Massachusetts, experienced a damaging earthquake that shook New Hampshire also. The 1755 Cape Ann earthquake, estimated magnitude 5.5–6.0, also shook most or all of New Hampshire. On November 9, 1810, Exeter experienced an estimated intensity VI tremor. It was accompanied by an unusual noise like an explosion, and broke windows in Portsmouth. Concord, the capital, experienced a series of shocks between 1872 and 1891. One earthquake was felt in late 1872, lasting ten seconds in Concord, and was felt in Laconia and other towns to the north. Ten years later, another tremor was strongest in Concord, although Dover and Pittsfield reportedly had buildings shaken. On November 23, 1884, a light shock was followed fifteen minutes later by a severe earthquake in Concord. The second shock was felt in Massachusetts, Connecticut, and eastern New York. Concord's last tremor in that period was mild and was reported in Cambridge and Melrose, Massachusetts. Southeastern New Hampshire and Maine experienced an earthquake in 1925. Dishes and goods were jostled from shelves in Ossipee, Tuftonboro, and Effingham Falls. In 1929 the Grand Banks of Newfoundland experienced a magnitude 7.2 earthquake and New Hampshire felt minor effects. In 1935, a 6.25 earthquake centered in Timiskaming, Ontario, away, was felt in an area of over, and some places in New Hampshire experienced Mercalli Intensities as high as V. Ossipee Lake was the site of two moderate earthquakes in December 1940. The quakes were felt in all six New England states, as well as parts of New Jersey and Pennsylvania. In the epicentral area, a large number of aftershocks happened. One observer counted over 120 aftershocks through January 31, 1941.
