Issues

Front: On 6 February 2018 an M_w 6.4 earthquake shook the city of Hualien in eastern Taiwan, at the leading edge of a modern arc–continent collision. The surface rupture resulted in severe damage to several tall buildings and caused 17 deaths, as well as 289 injuries. Although the Hualien area has one of the highest rates of seismicity in Taiwan, the geologic structures responsible for active deformation were not well understood before this event. The SRL Focus Section on the 6 February 2018 M_w 6.4 Hualien, Taiwan, Earthquake (this issue) presents new data and insights through 11 articles that investigate various aspects of this recent earthquake sequence. In this view, Yen et al. (this issue) consider one structural interpretation of the faults involved in the Hualien event’s seismic deformation; the images below, from Wu et al. (this issue), compare shake maps generated from earthquake early warning (EEW) networks in Taiwan, which was one of the first countries in the world to implement EEW.

Back: Before the era of digital seismic data collection began in the late 1970s, an estimated 4 million day-long seismograms were collected through the efforts of the World-Wide Standardized Seismograph Network (WWSSN). About 3.7 million of those seismograms remain archived today in the form of film chips. Alejandro et al. (Data Mine, this issue) document the preservation and cataloging of these records. Among the events recorded on the archived film chips are the 9 February 1971 M_w 6.5 San Fernando, California, earthquake (top); the 27 March 1964 M_w 9.2 Alaska earthquake, an example of a “disappearing trace” due to high-trace velocities (center); and aftershocks of the great Alaskan event that were observed on 28 March 1964 (bottom).