Earthquake-Triggered Ground Failure associated with the M9.2 1964 Great Alaska Earthquake

The M9.2 1964 Great Alaska earthquake is the second-largest earthquake in the historical record, the largest in North America, and involved nearly five minutes of shaking (Brocher and others, 2014). The earthquake initiated in the Alaska-Aleutian subduction zone, about 12 km below northern Prince William Sound. The rupture length was about 700 km and generated deep and shallow landsliding and widespread liquefaction over an area exceeding 200,000 square km. Peak ground accelerations reached ~50% g (USGS, 2016). The earthquake also generated a large tsunami that caused damage and fatalities as far south as California (Brocher and others, 2014).

This important event has been extensively studied, yet a digital compilation of ground failures from the event has not been created until now. Data from consequential historic events like the Great Alaska Earthquake are valuable for understanding the extent of impacts and improving the accuracy of predictive ground failure models. Ground failure data from historical events are not often digitized and are, therefore, relatively inaccessible for quantitative analyses. We present a digital compilation of about 1500 ground failure observations interpreted from numerous publications examining the 1964 earthquake (Figure 1), mainly from the USGS Professional Papers about the earthquake (papers 541-546). This series began as reconnaissance after the earthquake and broadened into many detailed investigations on the effects of the earthquake. This data release merges these observations into a single inventory with detailed feature attributes, descriptions of which can be found in Table 1. An interactive web version of the map is available as well. The most difficult challenges with this effort lay in handling uncertainties in the feature locations, and in the variability of the data quality due to the range in map and description scales of the publications. To address these issues, we compared the published information to historical topographic maps and local records, and included three attribute fields describing different types of uncertainties for each feature. These attributes are essential to understanding the limitations of the dataset and for using the observations appropriately for analysis.