强震仪是一种测量强烈活动的的地震仪，简单而言就是用于测量地震的加速规。它们通常装在一个盒子里，并且已经连接到互联网上。

强震仪可以用来测量一些地面运动非常强烈，而致超出一般地震仪测量范围的地震。它们会被放置在主要的断层附近，所得的数据(如断层破裂前缘的前进速度)并非一般地震仪所能查量得到。例子之一有帕克菲尔德实验(Parkfield Experiment)，当中大量设置了强震仪。

强震仪记录地表加速度峰值(Peak Ground Accerleration, PGA)、地表速度峰值(Peak Ground Velocity, PGV)、地表位移峰值(Peak Ground Displacement, PGD)及谱线强度(Spectral Intensity, SI)。

An accelerograph can be referred to as a strong motion seismograph, or simply an earthquake accelerometer. They are usually constructed as a self-contained box, more commonly now being connected directly to the Internet.

Accelerographs are useful for when the earthquake ground motion is so strong that it causes the more sensitive seismometers to go off-scale. There is an entire science of strong ground motion, that is dedicated to placing accelerographs in the vicinity of major faults. The type of information gathered (such as rupture velocity) would not be possible with the standard seismometers. The best known example is the Parkfield Experiment which involved a massive set of strong motion instrumentation.