We present a novel method for measuring the fluctuating basal normal and shear stresses of debris flows by using along‐channel seismic recordings. Our method couples a simple parameterization of a debris flow as a seismic source with direct measurements of seismic path effects using empirical Green's functions generated with a force hammer. We test this method using two large‐scale (8 and 10 m³) experimental flows at the U.S. Geological Survey debris‐flow flume that were recorded by dozens of three‐component seismic sensors. The seismically derived basal stress fluctuations compare well in amplitude and timing to independent force plate measurements within the valid frequency range (15–50 Hz). We show that although the high‐frequency seismic signals provide band‐limited forcing information, there are systematic relations between the fluctuating stresses and independently measured flow properties, especially mean basal shear stress and flow thickness. However, none of the relationships are simple, and since the flow properties also correlate with one another, we cannot isolate a single factor that relates in a simple way to the fluctuating forces. Nevertheless, our observations, most notably the gradually declining ratio of fluctuating to mean basal stresses during flow passage and the distinctive behavior of the coarse, unsaturated flow front, imply that flow style may be a primary control on the conversion of translational to vibrational kinetic energy. This conversion ultimately controls the radiation of high‐frequency seismic waves. Thus, flow style may provide the key to revealing the nature of the relationship between fluctuating forces and other flow properties.

中文翻译：

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利用地震记录和经验格林函数测量泥石流的基力波动

我们提出了一种通过使用沿通道地震记录来测量泥石流波动的基础法向应力和切应力的新方法。我们的方法使用由力锤生成的经验格林函数，将泥石流作为地震源的简单参数化与地震路径效应的直接测量结合起来。我们使用两个大型（8和10 m ³）美国地质调查局泥石流水槽中的实验流量，由数十个三分量地震传感器记录下来。地震得出的基础应力波动在幅度和时间上与有效频率范围（15–50 Hz）中独立的测力板测量结果相比较。我们表明，尽管高频地震信号提供了频带受限的强迫信息，但脉动应力与独立测量的流动特性（尤其是平均基础切应力和流动厚度）之间存在系统关系。但是，这些关系都不是简单的，并且由于流动特性也相互关联，因此我们无法隔离以简单方式与波动力相关的单个因素。尽管如此，我们的观察 最值得注意的是，在流动过程中脉动与平均基础应力之比逐渐减小，并且粗糙，不饱和的流动锋面表现出独特的特性，这意味着流动方式可能是平移动力向振动动能转化的主要控制因素。这种转换最终控制了高频地震波的辐射。因此，流动形式可以提供揭示波动力和其他流动特性之间关系的性质的关键。