Dynamic spectrum and contours of the herringbone-like radio emission. (a) Zoomed-in dynamic spectrum from NDA, e-CALLISTO Birr, and ORFEES between 10 MHz and 200 MHz. This part of the spectrum shows the herringbone-like fine structure observed by ORFEES as well as the first type II burst observed by NDA. (b) Contours of the radio emission at 30% and 70% levels from NRH Stokes I (total intensity) observations at 150 MHz (blue), 173 MHz (purple), and 228 MHz (green). The contours are overlaid on running difference images observed by SDO/AIA at 211 Å. The time interval between the images used to produce the running difference images is 2 min. The two peaks in radio intensity in the left panel of b are outlined by rectangles and coined Box 1 and Box 2.