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Using Lake Records to Investigate Earthquakes in Stable Continental Interiors: Case Study of the 1638 M6.5 New Hampshire, USA, Earthquake

Description: 

In 1638 CE, an estimated M6.5 earthquake generated significant ground shaking in south-central New Hampshire, in the stable continental region of the northeast United States. Given the challenges of preserving fault surface rupture in low-strain, humid continental vegetated regions and limited historical accounts, the source and extent of shaking of this event remains poorly understood. Lacustrine paleoseismology is a tool to study the record of earthquakes in both high- and low-strain tectonic areas. To better constrain the character of the 1638 earthquake, we compiled and analyzed archived and published cores and core data from 12 lakes in the proposed epicentral region. As a starting point, we focused on lakes within the estimated, yet highly uncertain, ground-shaking Modified Mercalli Intensities (MMI) of V½ to VIII. Some previous cores from this area exhibit grain-size and composition changes that could be interpreted as promising evidence for shaking-related sediment disturbance or transport, consistent with other historical earthquakes studied in eastern US lakes. However, many of these cores were collected and studied in the context of climate and environmental studies, and an overarching consensus on the correlation and/or trigger of the deposits is largely unexplored. We seek to resolve the timing and character of possible disturbance deposits within these cores to determine if they may be attributed to the 1638 or earlier earthquakes. Our contribution aims to: 1) improve shaking intensity estimations by defining an area that experienced significant ground-shaking, and 2) identify older earthquakes using the 1638 earthquake signature in lakes as a historic analogue. This rich dataset of prior work may guide locations to extract additional cores to better characterize regional ground shaking from the 1638 and possibly older earthquakes.

Session: Subaqueous Evidence for Earthquakes, Coseismic Landslides, Tsunamis and other Cascading Hazards [Poster]

Type: Poster

Date: 4/15/2026

Presentation Time: 08:00 AM (local time)

Presenting Author: Jessica A. T. Jobe

Student Presenter: No

Invited Presentation: 

Poster Number: 162

Authors