This study investigates the response of the horizontal component of the geomagnetic field (H) during the geomagnetic storm of 23–24 April 2023, which was triggered by an Interplanetary Coronal Mass Ejection (ICME). This storm provides a unique opportunity to evaluate the responses in H corresponding to the passage of shock, sheath, and magnetic cloud (MC) structures associated with the ICME. To fulfill this objective, the latitudinal profiles of H-variation are presented for the two distinct cases of the Indian ( \(75^\circ \) E) and American ( \(75^\circ \) W) sectors. It is found that: (i) latitudinal variances in the phase, amplitude and modulations of H-variation are significant, with amplitude decreasing from mid- to low-latitude, (ii) even though the two longitude sectors had distinct local times throughout the passage of the ICME structures (shock, sheath, and MC), significant storm-induced H-variations of ionospheric/magnetospheric origin are seen, and (iii) H-variation during the passage of sheath and MC region are anomalous, particularly over the Indian longitude sector. The observations showed a reduction of amplitude 350 nT (20:00 UT, April 23) in H-variation at mid-latitude station NVS in the Indian sector during the passage of the CME sheath compared to a reduction of an amplitude of 125 nT (02:45 UT, April 24) during the passage of the MC. These aspects are discussed, and important insights on the response of the terrestrial H-component corresponding to the arrival of different structures in ICME are presented.
